Lake Mead has risen more than 3 feet over the past month, and nearly 13 feet since Jan. 1.

The lake, which supplies 90% of the water used in the Las Vegas valley, is bucking the trend of the past five years. Lake Mead typically drops beginning around April, following a seasonal pattern.

As snow melts upstream in the Upper Colorado River Basin, water is held back in dams all along the way to prepare for higher consumption during the hot summer months. Water eventually reaches Lake Powell before flowing through the Grand Canyon and into Lake Mead.