Keep chains handy as late-season snowstorm heads to Sierra Nevada

A potent snowstorm could soon hit the Sierra Nevada Mountains of eastern California, putting a damper on travel for the second half of the week. The late-season winter storm may bring significant accumulating snow to the higher elevation passes along the entire range. Drivers hauling loads through the region will probably have to chain up at some point, so don’t be caught off guard.

Source: NOAA

Set Up

A cold front will help produce the unsettled weather beginning Wednesday night, May 15. Valleys and coastal areas of central California will get drenched by some heavy rain and thunderstorms. However, many mountain roads and communities will be snow-covered under much colder temperatures. The storm should be out of the region by the morning/midday (Pacific Daylight Time) on Friday, May 17.

Idamis Del Valle, a meteorologist with the National Weather Service (NWS) in Sacramento, California told Freight Waves that snow in mid-May in the Sierra Nevada isn’t abnormal. However, she expects this storm to be stronger than normal for this time of the year.

“Generally, in mid-May, storms produce four to eight inches of snow, depending on elevation. This storm could produce a foot or more,” said Del Valle. She described the impending snowfall as “not extremely rare, but unusual.”

High-Impact Areas

Snow will start to fall at elevations around 8,500 feet on Wednesday evening, dropping through the day on Thursday to around 5,500 feet. The NWS is forecasting some of the highest snow totals to occur near and south of Yosemite National Park, in the southern Sierra Nevada. This includes Camp Nelson, Devils Postpile, Fish Camp, Florence Lake, Giant Forest, Grant Grove, Lake Thomas Edison, Lodgepole, Shaver Lake and Tuolumne Meadows. These areas are mainly between US-395 and the Sacramento Valley. Total snow accumulations of up to 24 inches are possible, with blowing snow and reduced visibility as wind gusts may reach 35 mph.

In the northern Sierra Nevada, areas near Lassen Volcanic National Park, as well as western Plumas County and the western slopes could receive 12 to 18 inches of snow, with isolated spots of up to three feet. This will delay loads moving on I-80 over Donner Pass, in addition to US-50 over Echo Summit and CA-88 over Carson Pass.

Parts of the eastern slopes, including Aspendell and Whitney Portal, could get up to 12 inches above 9,000 feet, with two to five inches of snowfall between 7,000 and 9,000 feet. Also, these areas could get battered by 50-mph winds, leading to possible damage and power outages. Besides extremely limited visibility, drivers may get stopped in their tracks by downed trees or power lines blocking routes.

Chain Law Review/Impact on Freight

SONAR Road Conditions: Wednesday, May 15, 2019 at 11 p.m. EDT

Roads will turn from wet Wednesday evening to slushy and snowy Wednesday night, especially after midnight. Because changes in the weather can occur quickly in California as drivers change elevation, it’s important to remain aware of the chain laws.

According to the Owner Operator Independent Drivers Association (OOIDA), California does not require truck drivers to carry chains during any specified time period during the year. When the weather hits, though, it takes at least eight chains for a standard tractor-trailer configuration to comply with the regulations.

The California Department of Transportation (Caltrans) says that when chain controls are established in the Golden State, signs will be posted along roads indicating which of the three following levels of requirements is in place:

  • Requirement 1 (R-1): Chains are required on all vehicles except passenger vehicles and light-duty trucks under 6,000 pounds gross weight and equipped with snow tires on at least two drive wheels. Chains must be carried by vehicles using snow tires. All vehicles towing trailers must have chains on one drive axle. Trailers with brakes must have chains on at least one axle.
  • Requirement 2 (R2): Chains or traction devices are required on all vehicles except four wheel/all wheel drive vehicles with snow-tread tires on all four wheels. NOTE: Four wheel/all wheel drive vehicles must carry traction devices in chain control areas.
  • Requirement 3 (R3): Chains or traction devices are required on all vehicles, no exceptions.

The NWS has changed the Winter Storm Watch for the Sierra Nevada to a more serious Winter Storm Warning, in effect from Wednesday night through Thursday night. Check here for updates to official NWS winter weather alerts, and please be careful out there.

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Nick Austin, Director of Weather Analytics and Senior Meteorologist

In his 17 years of weather forecasting experience, Nick worked on air at WBBJ-TV and WRCB-TV, including time spent doing weather analysis and field reporting. He received his Bachelor of Science in Meteorology from Florida State University as well as a Bachelor of Science in Management from Georgia Institute of Technology. Nick is also a member of the American Meteorological Society and National Weather Association. As a member of the weather team at WBBJ-TV in Jackson, Tennessee, Nick was nominated for a Mid-South Emmy for live coverage of a major tornado outbreak in 2008. As part of the weather team at WRCB-TV in Chattanooga, Tennessee, Nick shared the Chattanooga Times-Free Press Best of the Best award for “Best Weather Team” for eight consecutive years. Nick earned his National Weather Association Broadcasting Seal in 2005.

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