For skiers and snowboarders, the map comparison above is the difference between a frown this time last year and a big smile now.

What you are seeing is the estimated snow depth in the Sierra Nevada Mountains, which straddle the border between California and Nevada.

(MORE: Ski information | Ski resort snow status)

A year ago on December 28 (left image), the area covered by snow was just 20.1 percent with an average depth of a paltry 1.3 inches. The storm track during much of the late fall and early winter last year was unfavorable for significant snow.

A year later, we've seen a complete reversal.

Multiple storm systems have slammed the mountain chain with heavy snow including Winter Storm Euclid, which dumped up to six feet of snow in the Sierra just before Christmas. Now the area covered by snow is 71.7 percent with an average depth of a little more than two feet. Areas shaded in pink on the image to the right have near or more than 100 inches on the ground!

It's been a complete reversal of fortune that is beneficial for not only those that like to hit the slopes, but also for California's water supply. Snow melting in the spring and summer funnels into reservoirs and accounts for one-third of the water supply for California's homes, farms and businesses.

MORE ON WEATHER.COM: - Winter Storm Euclid in Photos