March 21 may signal the beginning of spring in some places of North America. But not in California's Sierra. Yet one more snowstorm has brought powder to the region over the last four days, dropping feet of snow, not mere inches. So much snow has fallen in spring snowstorms at the Sierra ski resorts that many are setting records for season snowfall, and some resorts have extended their seasons.

The current storm rolled into the Sierra on March 18, dropping 5-to-8 feet of snow from Mammoth Mountain to Lake Tahoe. Avalanche advisories from the Sierra Avalanche Center bumped up to "considerable" based on wind slab formation and several weaknesses in the new snow layers.

Squaw Valley USA originally planned to open its High Camp swimming pool on Saturday, March 19, but too much snow caused the resort to postpone the opening until April 2. "It's not exactly weather that you'd want to be out there in a swimsuit," spokesperson Amelia Richmond told OnTheSnow. "This is the biggest storm of the year, and the powder was chest deep on me yesterday."

The resort topped the 500-inch mark for season snowfall last week, but is honing in on leaping beyond 600 inches. "We'll hit 600 inches today or tonight," Richmond said Monday morning. "It's among the really top years. We've only hit 600 inches two other times since 1970."

The storm caused both roads into Kirkwood Mountain Resort to close on Sunday, March 20, for avalanche control. "People living and staying at Kirkwood got their own private resort with Chair 6 open for the majority of the day," Prudence Wiesener, snow reporter, told us. "We had so much snow that safety is the biggest concern with lots of bombing for avalanche control."

The resort, which usually averages 500 inches of snowfall each season, posted 627-to-641 inches by Monday morning. Officials announced an extension of the ski season until May 1. "With this last dump, it will carry us through," said Wiesener. "All that's in our forecast in the near future is snow, too."

Sierra-at-Tahoe posted 625 inches of season snowfall by Monday morning, March 21. The resort surpassed its seasonal average of 480 inches in late February.

Heavenly Mountain Resort accumulated more than 5 feet of snow in four days during this most recent storm. The storm bumped the resort over 400 inches for the season, which puts it in the record books as its third-best season.

Northstar-at-Tahoe has seen the most snow fall in 25 years. Its summit snow base topped 200 inches in this storm. The resort sailed beyond the 500-inch mark for season snowfall and announced that it would extend the ski season through April 24.

Boreal Mountain Resort amassed 7.5 feet of snow in the weekend's storm. The new snowfall shot the resort into a record season with 679 inches of total snowfall.

Alpine Meadows recorded the snowstorm as its fourth-largest three-day storm, with 101 inches accrued at the summit.

Mammoth Mountain recorded up to 8 feet of snow in the storm cycle from Friday through Monday. Four feet of snow fell in upper elevations of the resort in 24 hours by Monday morning's snow report. Mammoth topped the 500-inch mark, a record it's only reached six times since 1970. But forecasts of continued snowstorms may well catapult this season to one of the top.

The storms in the Sierra are expected to take a short hiatus Tuesday and then launch into another wave pushing in Wednesday, according to the National Weather Service. Predictions call for the new storm, which is calculated to run through Sunday, to drop several more feet of snow.

More information.