Ice on Oscars' red carpet?

Wearing a strapless gown on the red carpet at Sunday night's Oscar Awards ceremony in Los Angeles could be a test of endurance for the actresses brave enough to try it.

An unusually cold air mass is filtering southward this weekend across California and then turning eastward into Nevada and Arizona.

A low pressure system ushered in the cold air, causing snow to fall at some very low elevations in the San Francisco and Los Angeles areas. There was a threat of snow in downtown San Francisco early Saturday, but only a few wet flakes of the white stuff were reported in the city.

In Los Angeles, snow levels Saturday are expected to drop to 1,500 feet, and possibly even lower during the heavier snow showers. In fact, snow could fall in the area of that big "Hollywood" sign that we've all seen on TV and the movies.

Temperatures on Sunday evening in Los Angeles could be in the upper 30s, which is well below average for this time of year.

This outbreak of cold air will be more than just a curiosity piece, I'm afraid.

A freeze warning is in effect for the central valleys of California, with temperatures expected to tumble into the upper 20s in places like Sacramento, Fresno and Stockton. Agriculture officials out there fear the freeze could be damaging to budding trees, such as apricots, almonds, peaches and plums.

A hard freeze could send produce prices (which already have soared in recent weeks because of cold weather and skyrocketing gas prices) even higher.

Believe it or not, snow is not unknown in San Francisco and in southern California.

Snow has been reported several times in downtown San Francisco, but the most recent occurrence was 35 years ago. The record is 3.7 inches, which fell on Feb. 5, 1877.

And 3 inches fell in Los Angeles on Jan. 19 and 20, 1949.

Farther east, the storm system is expected to bring showers to Phoenix, which could mean trouble for the NASCAR Spring Cup race scheduled there Sunday. By the way, an inch of snow also is possible late tonight or Sunday in Tucson.

That storm is expected to move into Colorado and then into the Midwest later Sunday and into Monday.