- ANCHORAGE, Alaska (AP) - U.S. Forest Service officials have issued a backcountry avalanche warning for the Chugach National Forest area. The warning comes after forecasts of weekend storms bringing unseasonable warmth and rain.   A lack of heavy snowfall has created a tenuous snow-pack on mountains in the Turnagain Arm area. The Chugach National Forest Avalanche Information Center has been listing the backcountry avalanche risk as "high" or "considerable" since December 24.