Weather
California Winter Weather Awareness Week Oct 25-31: What Makes a Blizzard?
Sacramento, CA – Winter Weather Awareness Week begins Sunday, October 25, with an important question for California residents: What actually makes a winter storm a blizzard? From the Sierra Nevada to
By Nolan Pierce · 2026-10-25T17:53:02.404Z
Sacramento, CA – Winter Weather Awareness Week begins Sunday, October 25, with an important question for California residents: What actually makes a winter storm a blizzard? From the Sierra Nevada to Southern California's mountain communities, powerful winds and heavy snow can create dangerous travel conditions.
According to the National Weather Service NWS , a blizzard occurs when sustained winds or frequent gusts reach at least 35 mph, accompanied by falling or blowing snow that reduces visibility to one quarter mile or less for at least three hours.
Heavy snowfall isn't required. Strong winds can lift snow already on the ground, producing dangerous whiteouts even after new snowfall stops.
What's the Difference Between a Watch and a Warning? A Winter Storm Watch means significant winter weather is possible, giving residents time to prepare.
A Winter Storm Warning means dangerous winter conditions are expected or already occurring.
A Blizzard Warning indicates blizzard conditions are expected or underway. Travel can become extremely dangerous as visibility drops and drifting snow blocks highways.
What Should California Residents Have Ready? Before winter storms arrive, households should prepare emergency supplies, including:
Food and water: At least three days of nonperishable food and one gallon of water per person daily. Warmth: Extra blankets, sleeping bags, insulated clothing and safe backup heating options. Emergency supplies: Flashlights, batteries, medications, first aid kits and charged power banks. Vehicles: A full gas tank, blankets, jumper cables, an ice scraper, a small shovel and emergency supplies. Snow removal: Shovels, ice melt, rock salt and traction materials. Carry properly fitted tire chains when required. Never operate generators, outdoor grills or other outdoor fuel burning equipment indoors or inside garages because of deadly carbon monoxide risks.
Why It Matters Across California From Sacramento and Sacramento County to Truckee, South Lake Tahoe, Mammoth Lakes, Fresno, Los Angeles and San Bernardino County, winter weather threats vary dramatically by elevation.
The Sierra Nevada is particularly vulnerable to blizzards. Powerful winter storms can produce intense snowfall, damaging winds and near zero visibility along Interstate 80 over Donner Summit and U.S. Highway 50 near Lake Tahoe.
U.S. Highway 395 along the eastern Sierra can also experience dangerous blowing snow and rapidly changing conditions.
In Southern California, mountain communities near Big Bear Lake and Wrightwood can experience heavy snowfall, icy roads and difficult travel, even while nearby coastal cities remain mild.
California's high elevation highways may close during major storms, and avalanche hazards can develop independently of official blizzard conditions.
Residents should check chain control requirements, avoid unnecessary mountain travel during warnings and prepare for possible power outages.
As Winter Weather Awareness Week continues through Saturday, October 31, residents are encouraged to review emergency plans, check supplies and monitor official NWS forecasts and Caltrans QuickMap road conditions.
Remember: A blizzard is defined by wind, visibility and duration — not snowfall totals.