After weeks of subzero temperatures, Anchorage finally got a warm up this week, and with it more snow. Enough, in fact, that on Friday the National Weather Service had issued winter weather advisory for Anchorage, Eagle River, Indian and Eklutna.

The notice came during an elongated rush hour, during which normally busy but passable streets became corridors of painfully slow progress.

Forecasters initially called for four to eight inches of snow in most areas, with snow accumulation of up to a foot on the hillside.

But by early Friday afternoon, the Alaska Department of Transportation had warned 18 inches of heavy snow was on its way to the Anchorage bowl, and the department was encouraging people to stay home and off the roads. The department is even pulling in equipment and drivers from other parts of the state to help with snow removal.

Meanwhile, avalanche forecasters are warning this new snow storm is overloading already overloaded slopes, creating a significantly risky situation for backcountry travelers.

The Chugach National Forest Avalanche Information Center calls the avalanche risk “considerable” and bluntly states “human triggered avalanches are likely on steep and/or wind loaded slopes ... expert level avalanche avoidance skills are important for anyone traveling in the backcountry today. Many areas of the backcountry should be avoided completely today.”

Friday’s snowfall could add as much as a foot of new snow to slopes that on Wednesday received two to three feet of snow in Girdwood, Turnagain Pass and parts of the Kenai Peninsula, according to the avalanche information center.

Roadways that hug mountainsides and cut through valleys are also in prime avalanche terrain. A natural avalanche closed the Seward Highway earlier this week near the Sterling Highway intersection, and the danger isn’t over.

The state’s transportation department has put the word out that small-to-medium size avalanches are likely, and urged drivers who can’t avoid the Turnagain/Seward Highway area to get directly to their destination without taking any unnecessary stops.

Road corridors with avalanche warnings include the Seward Highway between McHugh Creek and Twenty Mile River (Milepost 81), and also closer to Seward between Summit Lake Lodge and Milepost 21. A similar warning is in effect in Wasilla for the Palmer Fishhook Road from the Little Susitna River to Willow Fishhook Road.

In addition to being aware that a slab of snow could come crashing down at any time, DOT has warned that driving is difficult in the current weather conditions. Snow and wind make it difficult to see, the roadways are slick in spots, and road-clearing equipment adds another obstacle to avoid.

Contact Jill Burke at jill(at)alaskadispatch.com