January 07, 2004

Flood Watchers Wait For Signs Of 'Pineapple Express'

As this storm began, there was much discussion about whether or not it could lead to a repeat of the 1996 storm which resulted in the second-largest Portland flood of the past 100 years. Predictions tended to argue against the type of warming trend necessary to make it happen.

According to this Associated Press article (also available via KGW), now the conversation is turning to comparisons between Portland's current weather situation and the first-largest Portland flood of the past 100 years:

Experts say the storm lashing Oregon this week has two of the three tell-tale signs which preceded the 1964 deluge.

"To get a big flood, it's like baking a cake," said George Taylor, the state climatologist. "There's a recipe and it has three ingredients. Two of them have already been met," he said.

First, a wet autumn fills the rivers and saturates the soil. Then, the snow starts to fall.

The snowpack becomes a ready source of water, if an atmospheric event should cause it to melt. Both the wetness and the depth of snow this winter mirror the measurements taken in the weeks before the 1964 "Christmas Flood."

But it's the third ingredient, the so-called "Pineapple Express," which will make or break the flood prediction.

Courtesy KGW

With the first two ingredients already in place, Taylor says that satellite pictures do, in fact, display "a big sucker, like a left hook about to hit us in the chin." However, the article says that, despite the difficulty in determining in advance "how much rain will come out of these kinds of systems," Taylor is "cautiously optimistic" that this third ingredient isn't likely to make the necessary appearance.

Posted at 10:57 PM | PermalinkComments (1) | TrackBacks (0)
More In Et Cetera

« Previous Next »