Two NASA satellite images released late Monday by the National Weather Service office in Sacramento starkly illustrate how much less snow is covering the Sierra Nevada this week compared to the same time a year ago.

The images, taken from roughly 438 miles above Earth, show California’s Sierra Nevada range. In the first, from Feb. 18, 2019, the region is blanketed with snow. On that day, the snowpack, which is the source of about one-third of the state’s annual water supply, was at 147% of its historical statewide average for that date.