(CBS SF) — California ski resorts are opening up the slopes early thanks to a hefty snowfall and cold weather.

Boreal near Lake Tahoe plans to open on Friday in addition to Mountain High in Southern California.

Skiers and snowboarders flocked to Mammoth Mountain Thursday, the earliest opening since the drought began five years ago. The resort reported it was 16 degrees at the main lodge at 6 a.m. Friday.

A storm earlier in the week brought widespread rain and more than a foot of snow to the Sierra.

Combined with a cold, dry air mass, ski resorts were able to crank up their snow-making machines.