Winter storm warnings and warnings are in effect in seven states as heavy snow and dangerous travel conditions are expected over Christmas.

The National Weather Service (NWS) has issued winter storm warnings in Washington and Alaska, while winter weather warnings are active in those states as well as Oregon, Idaho, Montana, California and Nevada.

A winter storm warning means severe weather with heavy snowfall of at least 6 inches in 12 hours or 8 inches in 24 hours or significant sleet accumulations. A winter weather warning indicates less severe conditions but still warns of snow, sleet or freezing rain that could pose a risk to travel.

Here’s the latest state-by-state breakdown:

Washington

Washington faces widespread winter storm warnings and advisories, with up to three feet of snow forecast.

Warning areas:

• Olympics: Between 7 a.m. PST Wednesday and 4 p.m. PST Thursday, areas above 4,000 feet, including Quinault, Hurricane Ridge and Amanda Park, may experience up to three feet of snow and wind gusts of up to 40 mph, which leading to slippery roads and limited visibility.
• Upper slopes of the Eastern Washington Cascades Crest: Heavy snow is expected from 1:00 p.m. PST Wednesday through 10:00 p.m. PST Thursday, with accumulations of 6 to 18 inches above 3,000 feet. Areas like Roslyn and Easton are advised to prepare for hazardous driving conditions and carry emergency supplies.
• Lower slopes of the Eastern Washington Cascades Crest: Snowfall of 6 to 12 inches above 3,000 feet is forecast from 4:00 p.m. PST Wednesday through 10:00 a.m. PST Thursday. Places like Cliffdell, Cle Elum and Appleton will experience poor visibility and difficult travel conditions.
• Western Slopes of the Cascades: Above 3,500 feet, heavy snowfall of one to three feet is expected from 10:00 a.m. PST Wednesday to 10:00 p.m. PST Thursday. Lower elevations could see 6 to 12 inches of snow, impacting Snoqualmie Pass, Stevens Pass and Crystal Mountain Ski Area.
• Western Chelan County: Between 1:00 p.m. PST Wednesday and 10:00 p.m. PST Thursday, up to 22 inches of wet, heavy snow will make travel difficult and may result in power outages. Holden Village and Stevens Pass are included in this alert.
• Central Chelan County: Snow accumulations of 9 to 16 inches are forecast between 1:00 p.m. PST Wednesday and 1:00 p.m. PST Thursday, with peak snowfall expected overnight. Leavenworth and Plain should prepare for dangerous travel and possible tree damage.

Consulting areas:

• South Washington Cascades: Snowfall of 3 to 8 inches is expected at lower elevations Wednesday evening through Thursday, increasing to 10 to 18 inches above 5,000 feet. Areas like Larch Mountain will experience gusty winds and difficult travel conditions.
• Northwest Blue Mountains: Snow accumulations of up to 10 inches are expected above 4,000 feet from 10 p.m. PST Wednesday through 4 p.m. PST Thursday. Meacham and Ski Bluewood Resort will experience reduced visibility and possible tree damage.
• Wenatchee Area, Okanogan Valley and Waterville Plateau: Snowfall of 1 to 5 inches (2.5 to 12 centimeters) is forecast Wednesday afternoon through Thursday, with up to 9 inches (22 centimeters) at higher elevations. Travelers should be careful, especially on Christmas night.
• Northeast Mountains and Okanogan Highlands: Snow accumulations of 5 to 20 inches are expected Wednesday afternoon into Thursday morning, affecting towns such as Kettle Falls, Newport and Colville.

Alaska

Winter weather warnings are in effect for Alaska, with heavy snow, blowing snow and wind gusts up to 40 miles per hour, causing dangerous travel and risks of frostbite.

Warning areas:

• Southern slopes of the Western Brooks Range, upper Kobuk Valleys and lower Koyukuk Valleys: Through 3 p.m. AKST Wednesday, heavy snow and blowing snow will produce whiteout conditions with gusts up to 35 mph and wind chills as low as -35°F . Affected areas include Walker Lake, Ambler and Shugnak.
• Upper Koyukuk Valley: Heavy snowfall is expected through 3 p.m. AKST Wednesday, with additional accumulations of 1 to 3 inches, along with wind gusts up to 40 mph and wind chills as low as -20°F. Communities like Allakaket and Bettles face difficult travel conditions.

Consulting areas:

• Central Brooks Range: Snow and blowing snow with accumulations up to 2 inches and wind chills as low as -40°F will continue at Anaktuvuk Pass through Wednesday morning.
• Eastern Norton Sound and Yukon Delta Coast: Snowfall of three to five inches combined with wind gusts up to 40 mph will reduce visibility and pose a risk of frostbite in Unalakleet and Stebbins through Wednesday afternoon.

Idaho

Significant snow accumulations are forecast for parts of Idaho on Thursday.

Consulting areas:

• North and Central Panhandle Mountains: Snow accumulations of 5 to 20 inches are expected from 1 a.m. to 1 p.m. PST on Thursday, with valley snow accumulations ranging from less than 2 to 10 inches. Hazardous travel conditions are expected in Sandpoint, Kellogg, Bonners Ferry and Lookout Pass.
• Northern and Southern Clearwater Mountains: From 1 a.m. to 1 p.m. PST on Thursday, snow accumulations of 3 to 10 inches are forecast, with the heaviest snow above 4,000 feet. Significant travel and activity disruptions are expected, particularly on Highway 12, impacting Dixie, Elk River, Pierce and Elk City.

Montana

Consulting areas:

• Kootenai/Cabinet Region: Snowfall of 1 to 6 inches is expected between Thursday morning and afternoon, affecting mountain passes as well as Highway 2 and Highway 56.
• Lower Clark Fork Region: Up to 6 inches of snow is forecast Thursday, particularly at Lookout Pass and Highway 200.
• Bitterroot/Sapphire Mountains: Snow accumulations of 1 to 6 inches are expected Thursday morning through the afternoon, making travel on Lolo Pass challenging.

Oregon

Snow and gusty winds are forecast for several mountainous regions in Oregon, creating dangerous travel conditions through Thursday.

Consulting areas:

• Southern Oregon Cascades: Snow accumulations of 5 to 26 inches are expected between Wednesday afternoon and Friday morning, with wind gusts up to 70 mph. Dangerous travel conditions, particularly for Wednesday evening and Thursday morning. Affected areas include Crater Lake National Park, Highways 51, 62, 138 and Snowmans Hill Summit.
• North Oregon Cascades: Snow accumulations of 3 to 18 inches above 4,500 feet, with gusty winds up to 45 mph, Wednesday afternoon into Thursday evening. Travel could be very difficult, especially on passes such as Santiam Pass and Larch Mountain.
• Northern Blue Mountains: Wet snow is expected above 4,000 feet, with total accumulations of 8 to 10 inches and gusty winds up to 45 mph. Impacts include difficult driving conditions, particularly Wednesday night into Thursday afternoon. Areas affected include Tollgate and Meacham.
• Eastern slopes of the Oregon Cascades: Snow accumulations of 10 to 20 cm above 4,000 feet, with gusty winds up to 50 mph, Wednesday afternoon into Thursday evening. Difficult driving conditions are expected, particularly around Sunriver and Sisters.

California and Nevada

Winter Weather Warnings are active throughout the Sierra Nevada, affecting both Eastern California and Western Nevada. Snowfall and strong winds are expected to create dangerous travel conditions.

Consulting areas:

• Lassen-Eastern Plumas Counties: Snow accumulations of 1 to 10 inches are forecast Wednesday night through Friday morning. Hazardous travel conditions are expected in Susanville and Portola.
• Greater Lake Tahoe Area: Snowfall of 5 to 15 inches and mountain winds of up to 90 mph are expected above 6,000 feet between Wednesday night and Friday morning. Areas like Truckee and South Lake Tahoe will face travel challenges and large sea waves.
• Mono County: Snow accumulations of 3 to 12 inches are forecast, with gusty winds through Friday. Dangerous conditions are expected in places like Mammoth Lakes.
• Western Plumas County and West Slope Northern Sierra Nevada: Snowfall of 5 to 10 inches above 6,000 feet is expected Wednesday night into Friday morning, with higher amounts at peaks. Slippery roads and chain requirements are likely.

Travel and security

The NWS urges residents in affected areas to limit travel during severe weather and carry emergency supplies such as flashlights, food and water. Drivers should prepare for sudden changes in visibility and icy roads.

As the winter storm progresses, more updates are expected from local authorities to guide residents and travelers through potentially hazardous conditions.