12 have died since snowstorm cut off towns in San Bernardino Mountains, officials say

SAN BERNARDINO, Calif. -- At least 12 people have died after powerful snowstorms pummeled the San Bernardino Mountains cutting off roadways to several towns, authorities said Wednesday.

"We continue to respond to calls for service for our mountain residents. To date, we have identified 12 individuals who were deceased. So far, we can only confirm (1), a traffic accident, as weather-related. The preliminary information in the other deaths does not indicate they are weather-related, but those investigations are ongoing," the San Bernardino County Sheriff's Department said in a statement to ABC News.

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Rare blizzard warnings went into effect in late February in the mountain ranges of Southern California as an arctic air mass plunged down the West Coast, plastering California's coast ranges and the Sierra Nevada.

In an extremely unusual event, staggering amounts of snow fell in the San Bernardino Mountains and the adjacent San Gabriel Mountains, where thousands of people live or visit communities at high elevations reached by windy, steep highways.

In the aftermath of the storms, residents found themselves unable to leave their homes.

San Bernardino County authorities said the snowfall was so great it exceeded the capability of plows to clear roads, requiring earth-moving equipment and dump trucks to pick up and move snow.

The video in the media player above is from a previous report.

The Associated Press contributed to this report.