We're continuing to see record dry conditions. A bit scary! This is a report from Stanislaus Natl. Forest
Forest Precipitation
Based on data from Pinecrest, Mi Wok and Groveland Ranger Stations, forest
precipitation to date is 57% of average. This is a drop from 63% a month
ago due to April being extremely dry (.18" at Pinecrest and Mi Wok; .12 at
Groveland). This is the driest March-April period on the forest based on
45 years data at the Pinecrest site.
It appears that this water year (2007-2008) will end with about the same
precipitation as 2006-2007. If so, this will be second driest back-to-back
year period on record, surpassed only by the extreme drought of '75-76 and
'76-77. This year is more deceptively dry than last because we had a lot
of snow in January and February. However, last fall was very dry and it
has essentially not rained in March and April.
Precipitation predictions for May show no rain through about the first
three weeks of the month. If May turns out to be below average this will
also be a record dry period for March-April-May.
Snowpack
Snowpack in the two main watersheds on the forest, the Stanislaus and
Tuolumne Rivers, is only about 55% of average. Water year runoff is
expected to be somewhat greater (about 63%) because it includes rain storms
from last fall.
Summary/Management Implications
With over 90% of the water year gone, it is certain that this will be a
very dry year. Last year was the 5th driest on record and this year will
be in the same range - it could even be drier the way it looks now.
The most significant items about this very dry year are that it is the
second in a row and that the spring period is record-dry. Both inidicate
an extreme fire hazard this summer, especially the latter since fuels are
already at record dry moisture for this time of year. This may result in
restrictions on forest recreation use sooner than usual and more
constraints on implementing vegetation management projects. The last two
consecutive dry years like this saw a massive increase in tree mortality
from bark beetle activity 1-2 years later. On the positive side, the
mosquitos shouldn't be too bad in the high country...
Jim Frazier
Forest Hydrologist
Stanislaus National Forest
jfrazier@fs.fed.us
209-532-3671 xt 205
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