The Sierra Avalanche Center says the danger rating for an avalanche in the Sierra has been raised to “Considerable” for the first time since the end of January. Avalanche risks had Highway 89 on the west side of Lake Tahoe closed around Emerald Bay. Alpine Meadows was closed all day Thursday due to the high avalanche danger and avalanche mitigation, and Squaw Valley also halted operations for the day because of the avalanche danger and high winds.