
Meteorologists: Storm to ‘hammer’ soaked state
Another warm atmospheric river is poised to dump several inches of rain – more than 6 inches (15 cm) in some areas – onto California’s already sodden landscape. The peak of the event is expected today, Tuesday, March 14, 2023, and will continue into Wednesday, March 15. This storm comes on the heels of an earlier storm, which produced prolonged, excessive rainfall over the weekend.
The National Weather Service (NWS) offered more dire predictions yesterday evening:
The environment will be very favorable for prolonged, terrain-enhanced rainfall along the central and southern coastline and the Sierra foothills. The global guidance and a majority of the hi-res guidance hammer this part of the state with 3 to 6+ inches of rain, some occurring over areas still dealing with the high stream flows of the previous, not-so-distant atmospheric river event.
Worse still, the NWS said the storm will melt some of the record amount of snow blanketing the Sierra:
Higher dew points are expected to infiltrate the region which will help prime the snowpack for melting and possibly expedited by the heavy rain, thus increasing the threat for rapid runoff and the areal coverage of flooding.
The NWS expects the latest atmospheric river event to stretch into tomorrow, Wednesday, March 15. Excessive rain will also move eastward across the U.S. and could also become a problem for parts of Arizona.
Meanwhile, meteorologists are discussing a system of intensity rankings for atmospheric rivers, similar to that for hurricanes. They are saying they hope the rankings will help keep people aware, and safe.
Foothills, interior flooding expected
As of late in the day on March 13, some parts of California were under mandatory evacuation orders, in anticipation of the coming storm, with FEMA urging residents to pay attention. Meanwhile, 40 of California’s 58 counties had already declared a state of emergency.
Extensive damage was caused by the weekend’s atmospheric-river-driven storm. Damage included a washed-out levee, a minor tornado and extensive, widespread flooding, the Sacramento Bee reported. The paper described the expected impact of the coming storm around the capital city and across the northern half of the state:
But virtually all of interior Northern California is again under a flood watch by the weather service due to this week’s incoming atmospheric river. Parts of the Sacramento Valley could receive up to 3 inches of rain from Monday night through Tuesday night, with as much as 7 inches possible in parts of the foothills.
The California Nevada River Forecast Center shows 16 rivers and creeks will rise above flood level, as of 12 a.m. PT (07:00 UTC) today, March 14. Most are located in the Sacramento and San Joaquin valleys. Thirty-four more waterways – stretching from the Oregon border to Mexico – are expected to rise above monitor stage.
Growing snowpack could mean weeks of flooding
Climate scientist Daniel Swain said the storm that hit California during the weekend acted to increase the Sierra snowpack.
This map plot of the SWE change over the past 24 hours really tells the tale–much snow melting and SWE losses below about 4.5k ft in elevation but large *gains* above that level. Classic "warm-ish" storm dipole pattern! #CAwx #CAwater [3/n] pic.twitter.com/LTEjrC6cUD
— Daniel Swain (@Weather_West) March 12, 2023
The added depth means the state has more snow piled in its mountain ranges than ever previously recorded:
Brief thread about…snow. As of this weekend, the Southern Sierra now appears to have largest snowpack in recorded history (as measured by snow water equivalent, or SWE). Not just for the calendar date, but for *any* date! #CAwx #CAwater [1/n] pic.twitter.com/FYmFXqs2yL
— Daniel Swain (@Weather_West) March 12, 2023
Swain warned that the weekend storm, despite its warmth, will likely add to those totals:
Snowmelt-amplified flooding has affected multiple smaller Southern Sierra watersheds, but this has so far been much less of a problem elsewhere. Even w/additional warm storm this wk, I expect net SWE will *further increase* despite more lower elev melting. #CAwx #CAwater [4/n]
— Daniel Swain (@Weather_West) March 12, 2023
And that could lead to severe flooding for weeks to come, starting perhaps as soon as the end of March.
But here, I'm honing in on potential for larger/mainstem rivers to experience more serious flood problems in medium term (i.e., the weeks to come). There is a truly enormous amount of SWE in the southern/central Sierra watersheds… #CAwx #CAwater [6/n]
— Daniel Swain (@Weather_West) March 12, 2023

Storms already turned deadly
An earlier atmospheric river had slammed California and the West Coast on Friday (March 10, 2023), with nearly the entire state experiencing “a dangerous rainfall event.” Already inundated from weeks of rainfall and snowfall, California underwent flooding over the weekend, as rivers overflowed their banks and poured into low-lying areas. At least two deaths occurred due to the flooding. And several communities were isolated.
Forecast updates and damage reports from all corners of the state filled social media.
What we’ve seen so far
A MODERATE risk is in effect in our Day 3 Excessive Rainfall Outlook. More details: https://t.co/FQU5sbmsxo pic.twitter.com/R1LR4xuLEw
— NWS Weather Prediction Center (@NWSWPC) March 12, 2023
GALLERY: Floods in California submerge communities in water as snow builds in mountains.https://t.co/ud5hUKuhvH
— FOX 28 Columbus (@fox28columbus) March 12, 2023
California's Devastating Flash Floods: Springville & Kernville Emergenci… https://t.co/Unzgvwa7mZ via @YouTube
— richard western (@rpwestern1) March 12, 2023
Floods due to fresh storm in California, evacuation as Pajaro River overflows
Watch!https://t.co/UK16IpkQ0j
— WION (@WIONews) March 12, 2023
The atmospheric river has arrived in the West.
The system brings dangerous, flooding rain and heavy snow. pic.twitter.com/pLfHozHzRc
— CIRA (@CIRA_CSU) March 10, 2023
Urban areas and highways also impacted by atmospheric river
DRAMATIC VIDEO: An urban search and rescue task force in California was performing rescues by boat.
The levee near Pajaro, CA failed early Saturday. #CAwx #flood pic.twitter.com/75mZ3lO5K4
— WeatherNation (@WeatherNation) March 12, 2023
A closer look at 101 in Gilroy. Southbound lanes are closed.
NB lanes closest in the video, SB on other side.(Vid from 10:15, right before it was closed.)
The latest info: https://t.co/T0cs8aAhi7 pic.twitter.com/6qUlCX9KTs— Ian Cull (@NBCian) March 10, 2023
Castro Valley Rd closed near Gavilan College in Gilroy. (Video from 9:45 am.) #CAwx #CAflooding pic.twitter.com/2oSIn6ssdX
— Ian Cull (@NBCian) March 10, 2023
Heavy rain flooded Highway 12 and other streets in Santa Rosa, California. South of Santa Rosa in the Bay Area, flooding and mudslides washed out roads. #CAwx pic.twitter.com/mskfbwwQjI
— AccuWeather (@accuweather) March 10, 2023
Foothills of Central Sierra Nevada hit hard
Impacts of the latest atmospheric river in Kernville, CA pic.twitter.com/G1XB1mGvUA
— Brittney Beck (@brittney_beck) March 10, 2023
VIDEO: Catastrophic flash flooding in Springville, California. A PDS (particularly dangerous situation) FLASH FLOOD EMERGENCY ? is in effect for the region. More rain on the way. #cawx @JimCantore @weatherchannel @WeatherNation @foxweather VIDEO NOT MINE credit Brian Duke on FB pic.twitter.com/FEoG9otRgW
— Michael Gibson (@Geekflanka) March 10, 2023
Crazy #flooding in #Springville #California #atmospheric_river after heavy #rain and snow melt. Dozens of homes flooding, one collapsed and many more threatened to collapse. @jpetramala pic.twitter.com/4IAUf17QjK
— WxChasing- Brandon Clement (@bclemms) March 10, 2023
In Sequoia National Park
Video from this morning in the town of Three Rivers, several miles outside of Sequoia National Park. Reminder that Sequoia and Kings Canyon National Parks are closed to visitation. Roads nearby are hazardous and in places impassable. Please do not travel to the affected area! pic.twitter.com/zAszKozdhj
— Sequoia & Kings Cyn (@SequoiaKingsNPS) March 10, 2023
Rain-soaked coastal regions inundated
This isn’t good. Part of the community of Soquel in Santa Cruz County is cut off because Bates Creek washed out North Main Street in the storm #flooding pic.twitter.com/zSUbPEUkXx
— Kurtis Alexander (@kurtisalexander) March 10, 2023
In Santa Cruz County, San Lorenzo River topped its banks
The San Lorenzo River looked pretty wild this morning, just after its peak at 6 a.m. in Felton (20.35 feet) pic.twitter.com/WnLfX1GlJ8
— Kurtis Alexander (@kurtisalexander) March 10, 2023
Bottom line: Another atmospheric river will slam California today, March 14, 2023, bringing dangerous rainfall amounts and additional flooding. Look here for social media posts documenting the event.