Powerful storm prompts evacuations in California, threatens outbreak of tornadoes and wildfires across US this week

CNN

13-03-2025

A powerful storm is dropping drenching rain on flood-prone Southern California and heavy snow on the state's mountains. It's the first act of a storm that will unleash a severe thunderstorm outbreak, dangerous fire conditions and a blizzard as it crosses the entire United States in the coming days.
The National Weather Service issued flash flood warnings early Thursday morning for parts of Ventura, Los Angeles and Orange counties still recovering from devastating wildfires.
Emergency management officials in Santa Barbara, just north of Los Angeles, ordered residents in and around the Lake Fire burn scar to shelter in place starting Wednesday night, as 'flash flooding and debris flows may be imminent or occurring.'
'Residents are advised to stay inside and go to the innermost room in your home or to higher ground such as a second floor until further notice. DO NOT attempt to leave,' the county Office of Emergency Management warned.
The ongoing warnings for California came alongside a rare increase Thursday in the level of severe thunderstorm risk this storm will bring to the central and eastern US Friday and Saturday. Forecasters are increasingly concerned those regions will see a dangerous severe thunderstorm outbreak capable of multiple strong tornadoes.
As the storm arrived in the West on Wednesday, evacuation warnings urging people to prepare to leave at a moment's notice were issued for parts of Los Angeles County, while authorities ordered hundreds of residents in more vulnerable areas to evacuate ahead of the rain.
'The risk of mudflow and landslides is real,' Los Angeles County Supervisor Kathryn Barger said in a news conference.
The California Governor's Office of Emergency Services said Wednesday it has positioned rescue personnel and equipment in 11 counties where heavy impact from the storm is expected, including Los Angeles County.
In the Sierra Nevada, heavy snow brought travel to a standstill along part of Interstate 80 Wednesday night. Multiple crashes occurred in the snow along the eastbound portion of the roadway according to the California Highway Patrol.
Rain will continue Thursday with more than 20 million people across Southern California under flood watches until the afternoon, with a level 2 or 4 risk of flooding rainfall, according to the Weather Prediction Center.
The storm will track into the Rockies Thursday with additional rain, snow and winds. Winter weather alerts are in place across the highest parts of Nevada, Arizona and Utah, where snow could pile up to 2 feet. Gusts up to 50 mph across the West could make travel difficult and cause power outages.
Gusty winds will also impact the Plains and ramp up a widespread fire threat, especially from the late afternoon onward. More than 800 miles of the central US, from western Texas into South Dakota, are under a level 2 of 3 fire weather risk, according to the Storm Prediction Center. Any spark could turn into a wind-driven blaze in these conditions.
The fire risk will climb higher Friday in tandem with extremely strong winds. 'Significant, dangerous wildfire-spread conditions' are expected, and a wildfire outbreak is possible across parts of the Southern Plains, according to the center.
Those winds could gust up to 90 mph at times in parts of New Mexico, Texas and Oklahoma Friday, and also cause power outages and hazardous travel conditions, according to the Weather Prediction Center.
The storm will strengthen Friday in the central US and become unusually strong for March just before it tracks into an area where atmospheric conditions are primed to set off dangerous severe weather.
Severe thunderstorms will roar to life by the late afternoon in the Mississippi Valley, become more ferocious and pound potentially more than 900 miles of the region – from Louisiana to Minnesota – through the overnight hours.
A level 4 of 5 risk of severe thunderstorms is in place for parts of the region – including St. Louis – Friday, according to the Storm Prediction Center. Damaging winds will be widespread, with some storms producing gusts past 75 mph – on par with a Category 1 hurricane – within the level 3 and 4 risk areas.
Tornadoes and hail are also possible within any storm. Some of the strongest storms will be active after dark, adding another layer of danger: Nighttime tornadoes are nearly twice as likely to be deadly as those occurring during the day, a 2022 study found.
'All are encouraged to review their severe weather safety plans before Friday evening,' the National Weather Service in Central Illinois urged Thursday. 'Consider discussing the forecast with family/friends so they are aware in advance.'
Saturday poses another serious threat for dangerous thunderstorms and will see an increased threat of tornadoes, with the Storm Prediction Center pinpointing the South as the area of greatest concern for 'significant tornadoes, swaths of damaging (wind) gusts and hail.'
A level 4 of 5 risk of severe thunderstorms is in place Saturday for parts of Louisiana – including New Orleans – Mississippi, Alabama and the extreme western Florida Panhandle.
Severe thunderstorms could be ongoing early Saturday morning after Friday's activity, but the riskiest thunderstorms will intensify or develop by the afternoon in the South. Storms packing damaging wind gusts, tornadoes and hail will once again persist through the evening and overnight.
Setting the second-highest level of risk this far in advance is rare, and happens only when forecasters have great confidence that the ingredients for severe storms will be present. Over the past 15 years, level 4 risks issued three days in advance have resulted in an average of 90 tornado reports on the day of concern.
Similar instances in the past include the 2011 Super Outbreak centered in Alabama that killed more than 300 and was the costliest tornado outbreak on record. Another was the Easter Sunday Outbreak in 2020 that produced around 150 tornadoes and killed 35 people.
This story has been updated with additional information.
CNN's Robert Shackelford, Brandon Miller, Allison Chinchar and Kia Fatahi contributed to this report.