Being prepared means having snow tires or chains, Pritchard said.
He added when driving through snowy conditions, motorists want to leave a bigger cushion between their car and the vehicle in front of them than under normal conditions.
In addition, he said motorists should drive in the tracks of the vehicle in front because that allows their vehicle's tires to make contact with the pavement.
Pritchard said if a person is not used to driving in the snow, "they might want to consider just staying home."
Pritchard said people should not use bright lights while driving in dense fog. He advised driving at a speed safe for the conditions with the vehicle's normal lights on so the vehicle is visible to other vehicles.
Christopherson said as of 8:30 a.m., the storm had brought less than an inch of rain to the El Centro area but would bring more showers.
He added the storm is expected to bring the "first significant rain" of the year to the Imperial Valley.
The rain could continue through the early-morning hours Wednesday as the storm moves toward Arizona.
By afternoon Wednesday, the clouds will break and clear days are expected Thursday through the weekend.
Christopherson said the storm likely is slowing today's harvest of asparagus and lettuce.
Farmer John Pierre Menvielle said the rains are not stopping growers from harvesting their crops. He said it does slow but does not stop the effort.
"You have to keep going," he said. "You just don't hang out because of the rain."
He did say the rain could bring an upswing in prices because of a reduction of product.
Staff Writer Darren Simon can be reached at 337-4082.