It was quite surprising when the Sierra Nevada mountains were found to have no ice at all in April this year. According to a new report published in Nature Climate Change, this year’s snowpack level was the lowest in the past few centuries.

It was for nearly three-quarters of a century that the average depth of snow measured at Phillips Station, approximately 90 miles east of Sacramento, was found to be 66.5 inches. The snowpack is generally at its peak at the beginning of April.

Valerie Trouet, an associate professor of dendrochronology at the University of Arizona's Laboratory of Tree-Ring Research, said in press release of the university, "Our study really points to the extreme character of the 2014-15 winter. This is not just unprecedented over 80 years—it's unprecedented over 500 years".

The snowpack is an amassing of winter precipitation, which gradually melts in the period of warmer months to replenish lakes, streams, groundwater and reservoirs. As per the University of Arizona report, 80% of precipitation in California occurs in the winter, and the snowpack is responsible for 30% of its water supply.

According to Trouet, snow is a storage system occurring naturally and when it comes to a summer-dry climate like California, it becomes important that water could be stored and accessed in the summer when no precipitation is there.

The new study, titled "Multi-century evaluation of Sierra Nevada snowpack”, has been supported by the National Science Foundation, the Swiss National Science Foundation and the US Geological Survey.