By Yereth Rosen
ANCHORAGE, Alaska (Reuters) - The sole highway leading south from Anchorage was closed on Thursday after an early-morning avalanche swept through the mountains and over the road, state officials said.
Authorities said it was unknown how long the Seward Highway would remain closed, essentially cutting off travel between Anchorage and the Kenai Peninsula cities of Seward and Homer.
There were no reports of injuries following the 100-foot-wide avalanche, which swept down one day after a separate snow slide briefly closed the highway in the southern outskirts of Anchorage.
Rapidly warming temperatures, high winds and new snow and rain have created dangerous avalanche conditions throughout the region's Chugach Mountains, which are already loaded with near-record amounts of snow.
"We consider the risk level at `considerable' at this point in time," said Rick Feller, spokesman for the state Department of Transportation and Public Facilities.
That designation means small to moderate avalanches are likely, Feller said.
The department has advised motorists to avoid travel along the route, the mountain-lined Seward Highway, if possible.
"If you don't have to drive the Seward Highway corridor at this point in time, if you can postpone the trip, it would be advisable to do so," Feller said.
Backcountry travelers were also warned by managers of the Chugach National Forest that there are high to considerable risks of avalanches in the mountains south of Anchorage.
(Editing by Dan Whitcomb)