A storm system that dumped heavy snow in parts of California has moved eastward Thursday, threatening the southern Plains with severe weather and prompting the cancelation of hundreds of flights into and out of Dallas.

FlightAware.com reports Dallas-Fort Worth International Airport and Dallas Love Field have tallied more than 400 cancelations total, either to or from the airports, as the storm approaches the region.

Several school districts, including Dallas and Fort Worth have canceled after school activities and events because of the forecast.

"This is the same system that struck California and it's now in New Mexico and will be crossing Texas and then Arkansas," said Rich Thompson, lead forecaster for the Storm Prediction Center in Norman, Oklahoma.

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He said high winds and hail pose the greatest threats.

"The really intense tornadoes don't seem likely," Thompson said. "We think the biggest threat will be very large hail, baseball sized hail."

Meteorologists say the storm produced a "once-in-a-generation" snow in California and Oregon with up to 7 feet accumulating in spots.

The snowfall, however, is credited with helping reduce, and in some areas eliminate, drought conditions in California.