Surfers at a popular San Onofre State Beach spot say this weekend's shark attack will not stop them from surfing at the beach. 

"I’ve seen some sharks breach in the water and some pretty big dorsal fins in the water way out there, but I’m not alarmed by it whatsoever," said Kirt Nixon, an Encinitas surfer at San Onofre State Beach on Sunday.

San Onofre State Beach, from the nuclear plant to San Clemente, is closed until Sunday evening following Saturday's shark attack. Lifeguards will re-evaluate the water then. 

A woman was pulled from the water and airlifted to a nearby hospital after a shark bit her leg. The woman's rescuers said almost all the muscle in her leg was missing by the time they got her to the shore.

But the closure did not stop some surfers from getting into the water in nearby beaches. 

"As a surfer, I'm not going to let it deter me from surfing," said Nixon. "I've been surfing here ever since I was a little kid." 

Many surfers who spoke with NBC 7 said seeing sharks in the water off San Onofre State Beach was not uncommon. 

"On Easter Sunday, there was a sighting of a Great White breaching, as it was gobbling up a seal," said Mike Hurlbot, a resident.

Sharks are always out there, Nixon said. "I'm not too worried about it," he added. 

Kyle Baria, a surfer from San Marcos, said it was crazy to think someone was bit by a shark in a spot he frequented. 

"They’re out there, we know it," Baria said. "And we’d hate to see a friend get bit, we’d all rally to get that person out."

For other local residents, the sight of dolphins Sunday morning were an added reassurance. 

"There was a dolphin that rolled through the lineup a while ago and that always is reassuring," said Lee Watson, a San Clemente resident. "We like it when dolphins show up, the sharks don’t seem to like them as much. It makes you feel a little safer."

Former first lady Michelle Obama revealed Thursday behind-the-scene moments of how her two daughters, Malia and Sasha Obama, spent their night inside the White House the night before the inauguration.

Obama recalled the night as remarkably typical for a pair of teenagers. Malia and Sasha Obama, 18 and 15 respectively, said farewell to their previous home with a slumber party and pizza with friends.

"They had a sleepover, because of course on Inauguration Day, because my girls are so normal, they're like, 'Well, eight girls are gonna be sleeping here because it's our last time, and we want pizza and we want nuggets.' And it's like, really?" Michelle Obama said.

The disclosure came during a wide-ranging, but relatively politics-free, question-and-answer session at the annual American Institute of Architecture conference in Florida.

Obama said it was difficult for the girls to leave the only home they had known for the past eight years.

"So that moment of transition, right before the doors opened and we welcomed in the new family, our kids were leaving out the back door in tears, saying goodbye to people," she said.

Digital bandits breached 1.1 billion identities in 2016, nearly doubling their haul from the year before, according to a new study on cybercrime.

NBC News reports that the year brought more ransomware attacks and higher extortion demands, plus some of the biggest distributed denial of service attacks ever seen, causing "unprecedented levels of disruption" to internet traffic, according to the 2017 Internet Security Threat Report from Symantec.

"The bad guys made a lot of money last year," said Kevin Haley, director of Symantec Security Response. "They keep getting better and more efficient at what they do; they managed to fool us in new and different ways."

Cybercriminals are moving away from making money by stealing a little bit from a lot of people at a time, and toward attacking banks themselves, the reported noted. 

Two grand thefts at separate Apple stores in San Diego appear to be connected, according to San Diego police.

The loss at Fashion Valley Mall was worth approximately $20,000, said Paul Connelly, a SDPD Captain in the western division.

Thieves stole four MacBooks and at least 10 iPhones from demo tables at the Apple Store in Fashion Valley, according to employees.  

The UTC Apple Store in La Jolla was also robbed 30 minutes before the one in Fashion Valley, police confirmed. Officers responded to the Fashion Valley theft around 10:30 a.m. Friday.

Several suspects came into the store and grabbed the display items, setting off the alarm. Both burglaries at the separate stores had suspects with similar descriptions.

There are no reported injuries. San Diego Police Detectives could not release further information because it may jeopardize their investigation.

San Diego police released the following timeline of events in the deadly shooting at the La Jolla Crossroads apartment complex on Sunday, April 30.

Witnesses told NBC 7 the victims were celebrating a birthday party at the complex pool when the shooting began.

One woman died and seven people suffered gunshot wounds. Another person suffered a broken bone trying to escape the mass shooting.

A security guard was also fired at by Selis, but she got away without being shot.

The gunman has been identified as 49-year-old Peter Raymond Selis. Investigators said Selis was despondent over a recent breakup in a relationship in the days leading up to the shooting.

5:30 p.m.

Selis enters the pool area dressed in street clothes and carrying a backpack, according to witness Demetrius Griffin. Selis sits in a chair and places the backpack on a nearby table.

Griffin's friend who was celebrating his birthday approaches Selis to invite him to join the party.

Seconds later, Selis removes a gun from under his shirt and fires twice into the man's chest, Griffin said.

Selis continues firing, striking a man in his leg, one woman in her arm and chest and another woman in her leg, the witness said.

Selis reloads his weapon, according to police. Then he shoots a man in his abdomen, a woman in the neck region and another in her shoulder, according to Griffin.

6:06 p.m.

SDPD communications gets a call that two people are shot near the pool area.

A second caller says they heard five to seven gunshots and neighbors are yelling.

Officers are dispatched. SDFD is made aware of situation to send units

6:07 to 6:13 p.m.

SDPD dispatches 20 officers including the department's helicopter.

Additional callers report seeing at least 3 or 4 people in the pool area, suspect is a white male in his 40s.

More calls come in to communications center.

6:13 p.m.

The SDPD helicopter ABLE and ground units arrive on scene

SDPD ABLE pilot sees the suspect is in the pool area and he has a weapon

ABLE directs ground units to where the suspect is located in the pool area

As officers approach the pool area, the suspect fires his weapon, according to SDPD Chief Shelley Zimmerman.

The suspect continues to fire his weapon and point his gun at officers, she said.

Three of the officers shoot toward the suspect striking him.

Suspect is pronounced deceased at the scene.

A man who served as a rifleman and scout sniper with the U.S. Marines has been released by a Mexican judge after being arrested in Tijuana.

His sister Tracy Yeager issued a statement Monday that a Mexican Judge ordered the immediate release of her brother, Tyler James Yeager, 39, from custody.

“On behalf of her family, Ms. Yeager would like to thank the Mexican authorities for their courtesy and professionalism in this matter, the staff of the U.S. Consulate General in Tijuana, Montel Williams and his team as well as Tyler's attorney in Mexico, Fernando Benitez whose willingness to get involved was invaluable," said the statement.

Yeager's need to resume treatment due to his PTSD and addiction issues was emphasized in the statement.

"Mr. Yeager badly needs to resume treatment for his addiction and PTSD, and Ms. Yeager is committed to supporting her brother in ensuring he gets the help he needs," continued the statement.

Yeager was arrested on April 23 and charged in connection with a violent robbery with a gun, said Mexican officials. He was caught outside a Tijuana home that had just been robbed.

The Attorney General's office in Baja was investigating to determine if Yaeger was involved in those robberies as well.

Firefighters put out a brush fire Monday off the shoulder of northbound Interstate 15 near Poway Road. 

One acre burned around 12:48 p.m. on I-15 at Poway Road near Sabre Springs, according to San Diego Fire-Rescue crews. 

Heavy smoke was reported in the area. Crews jumped on the fire and contained it to just one acre.

No one was injured and no structures were threatened.

California Highway Patrol officials say the four, five and six lanes of NB I-15 and the Poway Road off-ramp were closed. 

No other information was available.

Cal Fire crews battled a small brush fire Monday in the Elfin Forest area of San Diego County.

No evacuations were called for in the fire reported at 1:30 p.m. along Seaquest Trail and Fortuna del Sur.

San Diego County Sheriff’s Department, Escondido firefighters and crews from the Rancho Sante Fe Fire Protection District helped fight the fire.

The fire was held to a quarter of an acre.

Firefighters will remain on scene for mop up.

A tornado that ripped through Canton, Texas, Saturday night lifted a black pick-up truck off a highway and dropped it more than 200 yards away in an empty field, killing the driver.

Brandon Edwards was driving on Texas Highway 64 with his wife and two young daughters when the tornado touched down about a mile in front of him. Edwards said he could “clearly” see the Dodge Ram flying through air.

Edwards, a Marine with medical training, said he knew he had to help and ran to the pick-up after the tornado had passed.

"There were barbed-wire fences ripped across through here. I didn't look at any of it. I just ran through it,” Edwards said. NBC 5’s Texas Thunder Truck captured video of several bystanders running toward the truck to help the victim.

The driver of the Dodge Ram was trapped in the truck and critically injured. Edwards said the injuries "were not survivable from the beginning."

The man in the truck could only say one word.

"He said, 'Help,' is all he said. I just kept saying, 'Hang on, please stay with us. If you can speak, speak to me," Edwards said, choking back tears. “I tried to keep him alive for a minute and see if I can get him at least some help."

Edwards said when he realized the man wasn’t going to survive, he decided to remain by his side anyways. The Marine said he wanted the unidentified man to know that he didn't die alone. Edwards said he is also hoping to find the man’s wife.

"Let her know that her husband did not die in that vehicle alone last night. That there were people trying to help him," Edwards said.

Edwards said he’s a disabled veteran. His dream is to be a firefighter, but he can't because of his injuries from military service. When we asked what it is that makes him run in, he said, "I still want to help."

A tiny beetle is responsible for wiping out thousands of trees in the Tijuana River Valley Regional Park, in particular willow trees.

The insect, known as the shot hole borer, is smaller than a sesame seed. It infiltrates trees with a fungus that quickly spreads under the bark.

The infestation became prevalent in the last year. One place where the devastation is visible is just off the Hollister Street bridge.

"All of those dead trees you see sticking up, those used to be green leafy trees that would block the view because they would be a wall of green willow," said Kyle Icke, Supervising Park Ranger, County of San Diego Parks and Recreation.

Icke initially thought some kind of chemical had been sprayed on the trees, until rangers discovered the shot hole borer had destroyed them.

The beetle preys upon willows because its bark is soft.

"It weakens the structure inside of the willow tree, makes it so the willow tree can't drink its water from its root and then it dies," said Icke.

California's drought has worsened the problem.

"Any natural resistance they might have is weakened, and they can't fight off the beetle as well," Icke added.

Scientists haven't found a way to stop the insect's destructive spread.

They believe the pest was somehow transported through a wood shipping crate from Southeast Asia to Southern California. 

"This pest is so new to our area, they're having a hard time figuring out how to call it. We haven't figured out a way to spray or do anything like that to combat it," explained Icke. "We physically have to remove the tree and chip them up so beetles can't continue living in those trees, and continue replanting. That's the best we can do, for now."

The trees in harder-to-reach locations that aren't an impediment to park visitors, are left where they are, so the local ecosystem is not interrupted.

In some cases, park rangers let nature take its course. They have noticed some of the willows are growing back. Even though the beetles destroyed the trunks, the roots were still alive, and the trees are growing back.

"It's very hopeful to us, seeing all these willow sprouting up, they're regrowing," said Icke. "We're very happy about that."

Park rangers are also fighting the beetle's infestation in other ways.

"When we do take trees down, we're planting trees at a ratio of 3 to 1," explained Icke. "So when we lose one, we plant three more trees in its place."

They are asking visitors not to remove any wood from the parks, so the invasive pest doesn't infect even more trees.

The staff at County of San Diego Parks and Recreation is continuing to survey its parks, and is working with other agencies to see how the area fares over time.

In the interim, rangers and scientists are learning about the insect's behavior, so they can develop action plans to track and stop the species from expanding.

For many families with teenage drivers, a new car just isn't in the budget.

According to an Insurance Institute for Highway Safety survey, 83 percent of parents who bought cars for their teen drivers said they purchased a used vehicle.

The IIHS has compiled a list of the safest, affordable used cars for teenage drivers. The recommendations are based on four principles: young drivers should avoid high horsepower; bigger, heavier vehicles are safer; Electronic stability control (ESC) is a must; and vehicles should have the best National Highway Traffic Safety Administration (NHTSA) safety rating possible.

The IIHS also recommends looking at the Vehicle Identification Number to check for outstanding recalls before buying a used vehicle. 

Here are IIHS' best choice cars for your teenage driver under $20,000. 

LARGE CARS 

• Volvo S80
  2007 and newer
  $4,000
• Toyota Avalon
  2015 and newer
  $18,800
• Infiniti M37/M56/Q70
  2013 and newer
  $19,800

MIDSIZE CARS

• Dodge Avenger
  2011-14
  $5,300
• Chrysler 200 sedan
  2011 and newer
  $5,900
• Kia Optima
  2011 and newer
  $7,600
• Volkswagen Passat
  2013 and newer; built after October 2012
  $8,700
• Volkswagen Jetta
  2015 and newer
  $9,200
• Nissan Altima sedan
  2013 and newer; built after November 2012
  $9,500
• Ford Fusion
  2013 and newer; built after December 2012
  $9,600
• Volvo S60
  2011 and newer
  $9,800
• Subaru Legacy
  2013 and newer; built after August 2012
  $10,700
• Chevrolet Malibu
  2014 and newer
  $10,900
• Honda Accord sedan and coupe
  2013 and newer
  $11,100
• Toyota Camry
  2014 and newer; built after December 2013
  $11,200
• Mazda 6
  2014 and newer
  $11,400
• Hyundai Sonata
  2015 and newer
  $11,900
• Acura TL
  2012-14; built after April 2012
  $12,400
• Lincoln MKZ
  2013 and newer
  $13,300
• Subaru Outback
  2013 and newer; built after August 2012
  $13,600
• Chevrolet Malibu Limited
  2016
  $13,700
• Toyota Prius v
  2015 and newer
  $16,300
• Volvo V60
  2015 and newer
  $18,400
• Audi A3
  2015 and newer
  $18,500
• Infiniti Q50
  2014-15
  $19,100

SMALL SUVS MODEL YEARS PRICE

• Mitsubishi Outlander Sport
  2011 and newer
  $6,900
• Mitsubishi Outlander
  2014 and newer
  $10,700
• Chevrolet Trax
  2015 and newer
  $11,800
• Fiat 500X
  2016 and newer; built after July 2015
  $12,600
• Nissan Rogue
   2014 and newer
  $12,900
• Buick Encore
  2015 and newer
  $13,800
• Subaru Forester
  2014 and newer
  $14,900
• Honda CR-V
  2015 and newer
  $15,600
• Hyundai Tucson
  2016 and newer
  $16,000
• Toyota RAV4
  2015 and newer
  $16,000
• Mazda CX-3
  2016 and newer
  $16,600

MIDSIZE SUVS 

• Volvo XC90
  2005 and newer
  $2,500
• Ford Flex
  2010 and newer; built after January 2010
  $7,200
• Chevrolet Equinox
  2014 and newer
  $12,100
• GMC Terrain
  2014 and newer
  $13,300
• Nissan Pathfinder
  2015 and newer
  $15,800
• Kia Sorento
  2016 and newer
  $16,500
• Volvo XC60
  2013 and newer
  $16,500
• Ford Edge
  2015 and newer; built after May 2015
  $17,400
• Nissan Murano
  2015 and newer
  $19,100

MINIVANS

• Kia Sedona
  2015 and newer
  $14,700
• Honda Odyssey
  2014 and newer
  $16,100
• Toyota Sienna
  2015 and newer
  $18,100

PICKUP

• Toyota Tundra extended cab
  2014 and newer
  $15,600

The IIHS has also compiled a list of "Good Choices" vehicles for teens starting under $10,000. You can see that list here.

First responders and swim instructors gathered at the YMCA in Santee to teach a water safety program Monday morning, in an effort to prevent drowning as swim season takes off.

The water safety program marked the beginning of National Water Safety Month.

A helicopter ambulance for east San Diego, Mercy Air 6, landed next to the Cameron Family YMCA's water park to kick start the event.

“Drowning remains the leading cause of accidental death for small children,” said David Atik, a Mercy Air 6 flight nurse, in a statement. “We take every opportunity we have to remind kids that they should become strong swimmers and always swim near a lifeguard.”

YMCA swim instructors joined the first responders to speak about pool safety and low-cost swimming lessons.

“We have water surrounding all of our communities here in San Diego, so it becomes really important for kids to know how to be safe in and around a swimming pool, and different types of water environments,” said Jojo Pope East county YMCA director of the association of aquatics.

About 10 people die a day from accidental drowning, making it the highest reason for unintentional injury or death in the U.S., according to the Centers for Disease Control and Prevention (CDC).

“We unfortunately know that kids drown within 10 feet of safety, under adult supervision,” said Pope. “A lot of our program is really to focus on those basic safety skills: teaching them how to jump into the pool, bounce off the bottom, return to the wall and return to safety. We also teach them the swim-float-swim, which are skills so they can get air if they become too tired.”

For the month of May, each YMCA in San Diego is offering a safety-around-water drowning prevention program free to the community.

Pope says the YMCA also offers family packages to teach the whole family how to be safe around water. The classes are open to children as young as six months, as well as adults.

Family members of the young woman attacked by a shark off the shore of San Onofre State Beach say she has a “rough road ahead.”

Leeanne Ericson was in a medically induced coma Sunday night at Scripps Memorial Hospital, her mother Christine McKnerney-Leidle told NBC 7.

“I can't imagine my daughter being in that water and the shark taking her under,” McKnerney-Leidle said through tears. “How scared she was. She must've been so scared, so scared.”

The attack happened Saturday shortly after 6 p.m. in a well-known surf spot nearby the San Diego County beach called Church. The surfspot is north of the now-closed San Onofre power plant near Basilone Road and Camp Pendleton.

The family was told the shark was 10 feet long. They don't know what type of shark it was.

The shark took the entire back of Ericson’s leg, missing her major arteries but damaging her nerve and tearing out muscle. It’s too soon to know what that means for the young mother of three, her parents said.

Ericson was camping with her boyfriend when she decided to swim while he surfed. She was comfortable swimming in the ocean, her mother said, since the family spent every summer surfing or swimming.

The couple saw a seal in the water and her boyfriend turned to swim out to a wave. Just then, Ericson disappeared from the water’s surface.

“She was gone. So he dived under to try and find her and couldn't find her,” Mark Leidle said. “He came up and the shark’s tail was sloshing in the water and she popped up and he grabbed her and put on the board.”

The surgeon told the family that if her boyfriend wasn’t there, Ericson would’ve died.

Good Samaritans rushed to help pull her to shore. One of the men had first aid training and used a surf leash to help slow down the bleeding.

Emergency personnel transported Ericson to a nearby hospital by helicopter.

Right now, doctors are watching Ericson for the potential of an infection or pneumonia from the sea foam she ingested in the attack, her mother said.

“At this point we’re just trying to keep her from getting any worse,” McKnerney Leidle said.

Once she clears those hurdles, the family is planning to help Ericson through months of recovery, possibly years.

Among the procedures she may face are reconstructive and plastic surgeries.

Walking will be a challenge.

“Her whole world is changed now,” her mother said. “All I can do is help her.”

As for the beach, it will be closed until Wednesday.

"Beach patrons are advised to heed warnings from local authorities to include Military Police, Area Guards and San Onofre Lifeguards as well as signage posted at the beach," the statement from Camp Pendleton’s Office of Communication read Monday morning.

Last year, there were an estimated 59 shark attacks across the U.S., according to data collected by scientists at the University of Florida.

“I’m shook. Emotionally, I’m really drained,” Rikky Galiendes said.

Galiendes was having what he described as a normal day in the La Jolla Crossroads apartment complex. He walked by the pool and saw a group of people swimming, eating BBQ and enjoying what was a normal Sunday afternoon.

Then, just about an hour later, he heard 8-10 gunshots from his apartment.

“It was really a gruesome scene. There was blood everywhere, blood on the corners. There were bloody footprints on the ground,” he recalled.

From his vantage point, he could see someone injured and instinctively called out to the man asking if he was ok. That’s when his roommate grabbed him and pointed out the gunman sitting with a gun on his lap.

That’s the image Galiendes can’t shake.

“The shooter just sitting down, relaxed, sitting down with a gun on his lap,” he said. “It’s really stunning. It’s hard to fathom.”

“How is this guy just sitting down there relaxed when all of this chaos is going on,” he said.

Galiendes said he's had friends and loved ones reach out to him to check on him but he has asked them to think about those who are in the hospital, injured.

“I’m just really like fed up. It’s just really hard to see that happening to people who were not expecting it to happen to them,” he said.

Please refresh this page for updates on this story. Details may change as more information becomes available.

Former Vice President Joe Biden will be in San Diego County this week.

He is scheduled to speak at the Fortune Brainstorm HEALTH conference in Carmel Valley Tuesday.

The conference runs for two days and brings together leaders to discuss healthcare in the modern age.

Mr. Biden is among the many speakers for this year's conference, which also includes Denise Morrison of Campbell Soup, John Mackey of Whole Foods and Dean of Stanford School of Medicine Dr. Lloyd Minor.

According to the website, "the forum will cover four pillars—personal wellness, intervention, research, and the value chain."

It will be held at the Fairmont Grand Del Mar hotel, Tuesday and Wednesday.

It began as a mystery for local water experts in San Diego County: numerous area streams showing the presence of caffeine, a stimulant with no natural source in California.

A team from the state’s Surface Water Ambient Monitoring Program (SWAMP) pulled samples from 85 different locations across the county and found caffeine in 49 locations. According to a February fact sheet, from the Regional Water Quality Control Board, the group was finding similar results year round in a seven-year period from 2008-2015.

According to scientists, caffeine is not typically toxic to aquatic organisms but it is a good indicator of other potentially harmful compounds usually found in wastewater, like extremely small pieces of plastic debris, viruses, pathogens, and pharmaceuticals.

Some of the SWAMP results weren’t that surprising, Casey Nogoda, a water resource engineer for the regional water board said. Finding caffeine in developed areas near wastewater treatment plants, near septic systems, leaky sewer lines and elsewhere with large concentrations of the public is expected, she said. What did stump them, was finding caffeine where there was little human activity, which according to the Board was “contrary to expectations.”

Nogoda did a lot of field work to analyze samples. She told NBC 7 Investigates, “the main puzzle was why were we finding in remote areas we considered pristine?”

She reviewed the data and noticed a pattern. In doing so, she was able to confirm and solve the mystery of the caffeine showing up in those “pristine areas.” The discovery?

“Where there was high recreational use we found caffeine hits, when there was wasn't we didn't find them,” Nogoda said.

In other words, she found the cause of the caffeine were people enjoying the outdoors, hiking, fishing or horseback riding, relieving themselves along the trails, sometimes directly into streams and lakes she suspects.

While it’s important for people to recreate “we don’t want them to destroy the habitat, Nogoda said. “Animals live in the stream, maybe the caffeine is okay in your body but it’s not okay for the bugs,” which live at the bottom of the stream. According to Nogoda, they supply the food for fish and other life living in and around the water systems that drain to major rivers and the ocean in our region.

One proposed solution is restroom facilities at popular trail locations.

The water board’s Senior Environmental Scientist Chad Loflen sent a letter of support for a United States Forest Service project for the popular Three Sisters Falls to provide, among other things, restroom facilities at the trailhead. In the letter, he noted the nearest public restroom was thirty minutes away by car.

A bill to help prosecutors convict predators who traffic in sex slavery passed in the California Senate Monday, announced a representative for Senator Toni Atkins.

Atkins created SB 230 to add sex trafficking, pimping and pandering to the list of crimes that does not allow character evidence to be used in a trial.

That helps add these sex trafficking crimes to a list of other offenses that prohibit character evidence, including cases involving sexual offenses, domestic violence, elder or dependent abuse and child abuse, said the statement.

"As a result of the complex and exploitative relationship between victims and their traffickers, cases of human trafficking, pimping and pandering are notoriously difficult to prosecute," Atkins said on the Senate floor.

"Additionally, much like victims of other sexual offenses, many victims of sex trafficking have been groomed, controlled or even brainwashed by their traffickers and do not see themselves as victims – at least not initially," added Atkins. 

"Thus, securing victim testimony in human trafficking trials is difficult."

The bill will help prosecutors consider a sex traffickers' prior activities as evidence related to their current ones, explained the statement.

"I want to thank my Senate colleagues for their bipartisan support for this sensible measure to help bring sex traffickers to justice," Atkins concluded after the vote.

Next, the bill SB 230 will be considered at the state Assembly, announced the statement.

In late March, Atkins introduced three measures aimed at combatting human trafficking. According to Senator Atkins, San Diego is one of three California cities on the FBI’s list of top 13 cities in the country for sex trafficking.

Forecasters expect at least one California river to hit flood stage later this week as a heat wave melts record snowpack in the Sierra Nevada.

Forecasters with the National Oceanic and Atmospheric Administration said Sunday they expect the Merced River in Yosemite National Park to go about a foot over its banks on Wednesday.

A wet fall and winter have brought the most rain and snow in history to California's northern Sierra mountains. The National Weather Service says a hot spell this week will raise Northern California temperatures to levels usually not seen until early July.

Forecasters are warning swimmers and others that some California rivers will run extra cold and fast while the record snow melts.

Local and state beaches may have borders, but sharks roam freely in the water. 

Shark attacks can be a scary possibility for families enjoying the warm weather and swimming in the ocean water.

But would you know what to do if you encounter a shark in the water? 

Experts say sharks are instinctive animals: they follow their food, and the currents. They can be difficult to predict. 

Paul "Doc" Anes with San Diego Shark Diving runs a shark diving business to get people close to Great Whites. 

He says the animals are not looking for humans to eat. Anes said he believes attacks come down to whether humans are in shark territory. 

"White sharks what they typically do is they'll come up and they'll do an exploratory bite, unfortunately they've got really big mouths," Anes said. "They're powerful animals. Their teeth are like scalpels, so they cause a lot of damage."

Doc Anes says there are many areas along the Southern California coast that are Great White Shark nurseries.

He also says oil from a whale carcass that washed ashore near area may be attacking sharks to certain areas.

Anes said shark bites are rare, but if you do see one, the last thing you should do is panic.

He has the following tips for swimmers: 

• Don't swim at early morning light or sunset
• Stay with a group of people
• Stay on a beach that has lifeguards or something similar, in case something does happen, so you have rescue personnel available to assist. 

Lieutenant Andy Larem with the San Diego Lifeguards said shark sightings along the Southern California coast are rare. Being attacked by one is even less likely.

"Statistics show you have a better chance of being struck by lightning," Larem said.

Last year, there were an estimated 59 shark attacks across the U.S., according to data collected by scientists at the University of Florida.