Frozen fog smothers Sisters

The Christmas season didn't bring snow, but Jack Frost certainly left plenty of hoarfrost on everything.

When a huge high-pressure system, such as the one we're living with now, meets up with very cold air from the north, the results for all of Central Oregon, Washington and clear into the interior of Canada, will often be frozen fog.

What little moisture is in the air is slowly converted to ice crystals and begins to stick to everything in the form of hoarfrost. Where there's adequate moisture, frozen fog becomes so heavy that it falls like snow.

Because high-pressure systems are usually stable, there are no surface winds to move the air mass (except in places like the Columbia River Gorge where very cold air is flowing into the lower, warmer, Willamette Valley).

Without the usual prevailing winds from the southwest, the big high-pressure zone sits motionless, causing an atmospheric phenomena almost like the little poem I learned in the 8th grade:

Fog comes in on little cat feet Sits on silent haunches Looking over harbor and city And then moves on.

My phone's been ringing off the hook lately over our current weather.

"I can't remember ever seeing this kind of weather before," most callers say.

Anyone who's lived in Central Oregon as long as I have can probably remember frozen fog only too well. I believe the longest period of hoarfrost we had in Central Oregon was in the late '80s. If I remember correctly, the temperature that year was in the -10 F range and the hoarfrost seemed to hold the cold on the land like an icy fist.

Pipes froze and everyone complained about the piercing cold without enjoying the beauty of the landscape coated with ice.

I remember this kind of weather in the Sisters area on at least four different occasions over the last 10 years.

Enjoy the beauty of hoarfrost while you can. As soon as low pressure - waiting in the Pacific - comes crashing into the coastal areas, the frozen fog will drift away and be replaced by snow in the mountains, followed by the bone-chilling Arctic Express that usually makes our life even more exciting in January and February.