An incoming snow storm this weekend will bring “major” travel impacts to the Sierra Nevada and Shasta County mountain ranges, with snow expected to rise to at least 3,000 feet between Thursday night and Friday morning.
“The snow levels will get up to about 8,500 feet during the peak of it — they will drop down a little bit, but not really until Saturday and when the [precipitation] is really letting up,” said National Weather Service meteorologist Bill Rasch in a Thursday briefing.
The weather service has placed both areas under a winter storm warning, under which travel is strongly discouraged due to “significant reduction of visibility at times”. An additional winter storm warning was issued for the northern Sacramento valley, including the Redding area, late Thursday afternoon.
The Shasta County winter storm warning lasts from 7 a.m. Thursday to 1 a.m. Friday, while the Sierra Nevada winter storm warning has been in place since 10 a.m. Thursday and will last through 10 a.m. Sunday.
The storm, a warm atmospheric river, will be followed by additional storms through the following week, and melting snow could result in potential flooding. Here are answers to questions about which areas are likely to flood, what to do if you’re snowed in and more.
Who should be aware of flooding?
Rasch, the meteorologist, said during Thursday’s briefing flooding is most likely to occur in the valley and foothills from Friday through Tuesday.
The weather service placed much of Northern California, including the Sacramento Valley and the upper San Joaquin Valley, under a flood watch from 9 a.m. Thursday to 10 a.m. Sunday.
Though Rasch says the highest risk is between Friday and Saturday, the weather service anticipates seeing some snowmelt from the warm atmospheric river storm happening this weekend, causing additional runoff.
That may continue as another storm is forecast to move through the area early next week: “All the snowpack changes from the current storm will lean into that one, the river and flooding results might be about the same though it’s a slightly different storm,” Rasch said.
The current snowpack is almost double the average amount for this time of year. Given that, scientists, like Andrew Schwartz, lead scientist at the UC Berkeley Central Sierra Snow Lab, say people living downstream of the snowpack should know there’s a possibility they may need to evacuate.
“The biggest thing and best thing that you can do to prepare yourself is just keep an eye on what the forecast is and what watches or warnings are currently out there,” Schwartz said. “Maybe treat it like forest fire season. Have a go bag ready in case you do need to evacuate quickly, but hopefully it doesn't come to that.”
What happens if I’m snowed in during a storm?
Take care when using a fireplace, stove or space heater, making sure to ventilate if possible and use fire safeguards.
If the heat goes out, the weather service advises it’s crucial to stay hydrated, since dry, cold air can quicken dehydration, and to eat when possible so your body can produce its own heat.
Wearing loose, warm layers of clothing is better than wearing one heavy layer, allowing for clothing to be removed (or added) to adjust body temperature accordingly. Closing unused rooms, blinds and curtains can help preserve heat, as can stuffing towels, rags or blankets in door cracks.
If you have a gas furnace that vents out the roof, the weather service urges people to turn off the unit until the snow melts. Proper ventilation is important so as to avoid carbon monoxide emergencies, which North Tahoe Fire says have been increasingly prevalent this winter due to heavy snow build-up on vents.
“Use caution while clearing snow from rooftops,” the department said in a press release, adding it has also seen an uptick in gas leaks from buried propane tanks, natural gas meters and propane plumbing this winter.
Fire Chief Steve Leighton also noted that an aluminum shovel or ladder that comes into contact with electrical lines connected to a utility line can “easily electrocute and kill a person.”
North Tahoe Fire encourages people to watch a best practices video it put together for propane snow safety.
If I have to drive in the snow, how can I do so safely?
A “winter storm warning” as determined by the weather service means travelers can expect major travel delays, possible road closures and intermittent reduced visibility.
However, under the National Oceanic and Atmospheric Administration’s Winter Storm Severity Index, the Sierra Nevada and Shasta County ranges are projected to see “extreme impacts” from the storm.
“Extremely dangerous or impossible driving conditions,” the index note reads. “Travel is not advised.”
If you must travel, go slowly. Fill up on gas before you go and monitor fuel levels closely.
There are tools you can use to track how snow might impact your route:
- The National Weather Service has an option to see an hourly weather forecast to track what snow levels (and precipitation) may look like during the length of your trip.
- Caltrans has a tool where you can insert a specific highway number or numbers to check any road conditions impacting it. (You can also call 1-800-427-7623 for information on current highway conditions.)
- The Caltrans QuickMap shows road conditions in real-time. Footage of highway locations is available via the Caltrans CCTV Map.
The California Highway Patrol’s acting commissioner, Sean Duryee, has urged anyone traveling through stormy weather to check their tires and windshield wipers before starting a drive.
“Make sure you have significant tread and that you can travel safely and your tires are inflated properly,” he said. “Either carry chains with you or have studded tires.”
Along with ensuring wiper fluid is full and blades are unbroken, other checks to make include your lights and coolant level.
“Check the cooling system for leaks, test the coolant, and drain or replace the old coolant,” the National Highway Traffic and Safety Administration recommends.
The NHTSA also has a list of supplies to bring in your car in case you get stuck in the storm:
- Blankets and extra clothes to layer for warmth
- Abrasive material (e.g. sand, kitty litter)
- A snow shovel, broom and ice scraper
- Jumper cables
- Flashlight
- Warning devices (flares and emergency markers)
- A cell phone and charger
- Water, food and any necessary medicine
If you can no longer see due to the snow, pull over until visibility improves and turn off lights so cars won’t follow you.
What happens if I’m stranded in my car during a storm?
Stay in your vehicle.
To stay warm, the National Weather Service says you can run the motor for about 10 minutes an hour, while lowering the window slightly to evade carbon monoxide poisoning. Clearing snow from the exhaust pipe when possible helps stave off potential gas poisoning.
If you need to be rescued, the weather service recommends tying a bright-colored cloth to your car’s antenna or door and, after snow stops falling, showing you need help by raising your car’s hood.
Where can I find weather updates?
The National Weather Service has multiple places you can stay updated on weather changes:
- See the National Weather Service map (click for warnings)
