The weather in California was fairly quiet last week, but that’s about to change. Snow is returning this week after many ski resort owners have already reported record snowfall this month. Unfortunately, this has caused travel nightmares, too. Torrential rains and flooding are coming back to the foothills, nearby valleys, and the San Francisco metro area, so travel through the region will once again become risky.
Snowfall will increase this afternoon (Monday, February 25) across the Sierra as a slow-moving low pressure system in the Pacific comes ashore. Snowfall will remain steady for about 60 hours, with snow levels beginning in the 4,500- to 5,500-foot range, rising above 6,000 feet by Wednesday. The biggest accumulations will likely hit the northern Sierra. Many areas of Western Plumas County will see two to six feet, with a massive six to eight feet possible over Lassen Volcanic National Park.
Portions of eastern Plumas County, including the city of Portola, as well as eastern Sierra County could end up with total snow accumulations of 18 inches above 4,5000 feet west of US-395; two to five feet totals above 6,000 feet. Besides very slick roads making travel hazardous, forceful wind gusts of 65 mph will make deadheading downright dangerous. Gusts over the tallest ridges could top 120 mph.
Snow totals to the south will pale in comparison from Donner Pass through Tioga pass, but two- to four-foot accumulations will keep snow plow operators occupied, and travel will be treacherous.
As is usually the case with these storms, the greater Lake Tahoe Area – including the cities of Incline Village, South Lake Tahoe, Stateline, and Truckee – will also get slammed. Look for two to four feet of snow to pile up, with four to eight feet above 7,000 feet in elevation. Winds may gusts as high as 60 mph, with gusts over 140 mph over the nearby ridges.
According to the National Oceanographic and Atmospheric Administration (NOAA), average snow coverage across the Sierra is about 10 percent higher than this time last year, but what’s more impressive is that the average snow depth along the range is nearly six times greater, now standing at 37.2 inches. The developing storm will only add to transportation troubles.
Carriers should avoid sending drivers through the Sierra this week, if possible. The snow alone will be a problem, but even worse will be periods of white-out conditions and limited/zero visibility. Closures on I-80 and other routes are inevitable, and delays will only cost companies valuable time and money. Winter Storm Warnings have been issued by the National Weather Service (NWS) and continue to be updated. Check chain laws here for the latest updates on winter driving.
The same storm that will make the Sierra snowbound will drench the lower slopes and foothills with flooding rain. San Francisco, in addition to the Central Valley from Redding to Sacramento to Modesto, are also in the target zone for heavy rain after flooding devastated the region just a week and half ago. Downpours will lead to rapidly rising river and creeks which could overflow their banks, and drainage systems may not be handle the excess runoff.
Soaking rain totals will range from two to five inches in the Central Valley (Redding to Modesto), to three to six inches in the Sierra foothills, with pockets of eight to 12 inches possible. Persistent rain heavy at times may lead to flash flooding in burn scar areas of the Camp, Carr, Delta, Hirz, and Mendocino wildfires. Mudslides and debris flows could potentially block roads.
In additional to the rain, wind gusts are expected to reach 45 to 60 mph. Trees and power lines could be blow down, leading to road blocks, loss of electricity, and property damage. Flood Watches and Wind Advisories have been posted.
Other Significant Weather This Week
Fuel gelling and brake failures could be issues from Montana through the Dakotas and into Minnesota. It’ll be very cold the first few days of the week with nighttime low temperatures in the teens and 20s below zero, and highs only in the single digits below zero to 10 degrees above. Drivers: be sure to pour enough winter additive in your diesel, and keep your trucks running as much as possible.
Another winter storm could strike the Midwest and Northeast again late in the week, along with the return of heavy rain in the Southeast.
Look for weather updates throughout the week on the FreightWaves website!