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©
2002 |
December
was seasonably wintry in these parts
December weather in Central Oregon
was decidedly winterlike, with chilly days, considerable cloud cover or
fog, and periodic snowfalls. Sunshine was a scarce commodity. Weather observers
at Black Butte Ranch and Sunriver noted mainly sunny skies on only five
dates.
During the shortest "days"
of the year, Christmas decorations and lights stood out in sharp contrast
to the gray, drab December weather.
With substantial snow having
fallen prior to Thanksgiving and periodically renewed during December,
there was no need for anyone in the Bend-Sunriver-Sisters area to sing
"I'm dreaming of a white Christmas."
One consequence of the cloud
cover was that on many days in December there was little difference between
maximum and minimum temperatures.
In Sisters, December maximum
temperatures ranged between 30 and 39 degrees F. on two-thirds of the
days; minimums were in the 20-29 degrees F. range -- also on two-thirds
of the days.
Sisters' maximum temperatures
averaged 37.7 degrees F., which was 3.3 degrees F. lower than the long-term
(1961-90) average of 41.0 degrees F. In fact, 41 degrees F. or higher
was reached on only eight days. Sisters' average maximum of 37.7 degrees
F. was almost identical to Bend's 37.4 degrees F.
Elsewhere, locally, Black
Butte Ranch and Sunriver had December maximum temperatures that averaged
34.8 degrees F. and 37.6 degrees F., respectively.
Normally, Sisters can expect
minimum temperatures to drop below 20 degrees F. on one-third of the nights
in December, including three in the 0-9 degrees F. range.
This past month, Sisters'
extreme minimum temperature was 20 degrees F. (December 28 and 29). This
is the first time (period 1961-2001) that Sisters' extreme minimum temperature
in December has not dropped below 20 degrees F.
Last year, minimums colder
than 20 degrees F. occurred on 18 dates and included three that were below
10 degrees F.
Picking up where November
left off, Mother Nature continued to keep the Pacific Northwest supplied
with moisture -- mainly in the form of snow in the Cascades and over the
Midstate Plateau. Precise measurements of precipitation, when it is in
the form of snow, is difficult to obtain, especially if the snow is windblown.
Nonetheless, precipitation
totals for Central Oregon weather stations used in this report are as
follows: Sisters 2.45 inches including 10.2 inches of snow, Bend 2.33
inches including 8.20 inches of snow, Black Butte Ranch 6.02 inches including
31.0 inches of snow, Sunriver 3.99 inches including 27.8 inches of snow.
There are remarkable differences
in precipitation amounts between Black Butte Ranch and Sisters.
This was again evident in
December. Except for Sunriver, a little of the precipitation was in the
form of rain which shrank the pre-existing snowpack --until the next snowfall
arrived.
Inclement weather periodically
made driving conditions difficult over the Santiam Pass during December
and traffic delays occurred on several occasions.
By the end of December, snowpack
and the water content of the snow were much above average in many parts
of Oregon.
Raymond R. Hatton is the author
of "Sisters Country Weather and Climate," "Oregon's Sisters Country,"
and other books on the region.
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