Western Drought Info

“Received this from one of my email networks. Interesting reading.

-------------------------------------------
From: Kelly Redmond [mailto:krwrcc@dri.edu]
Sent: Wednesday, April 24, 2002 11:23 AM
To: drought@ndmc.unl.edu
Subject: [Drought] roundup, finished

Howdy,

Been doing a lot of western roundups for various press purposes,
and am really struck by how not good things are starting to look.

First off, the streamflow forecasts for most of the 750 or so forecast
points are in the below average category. About the only real
exceptions
are in parts of the Cascades, northern and southern, and in the central
Idaho area, esp the Clearwater. The further east, and the further south
(especially) that one looks, the more the streamflows are forecast to
be below average. In Arizona, off the north slopes of the Rim, a number
of streamflow forecasts are in the single digits (percent of average,
usually Apr-July, the principal runoff season). In some places they
are below 5 percent of average. The Little Colorado, where it flows in
to Lyman Lake, is only projected at 4 percent of average. Walnut Creek,
to the west, had the lowest percentage at 3 percent.

Even on the Columbia, the streamflow forecast is only calling for 94
percent of average. Much of the Columbia is nearly run-of-the-river
storage, and replenishes itself reasonably rapidly, but not all
sub-basins share that characteristic.

The Klamath area, which had been looking in much better shape than
last year, is now not looking so much better, and is still a fair ways
below average. Streamflow forecasts there are in the 65-75 percent
range. Even the Deschutes, which has the unusual response that we see
in volcanic areas, is down at 85 percent. Rivers like this have
several-year response times.

In the Sierra, snowpack ended up near to a little below average,
maybe around 90 percent in the central part. But streamflows on the
Truckee and Carson and the Walkers are only projected in the 65-80
percent range, a lingering effect of last winter's drought, which
left the soils bone dry. Lake Tahoe is projected to only rise about
70 percent of its usual rise, so it will likely drop some more this
summer, toward the rim, where it shuts off the Truckee completely.

Looking into the Pinyon pine issue a little more, we found that a
representative station in the western Great Basin, Yerington, on the
lower Walker River, has had the lowest 36-month April-March total in
its history, 22 percent below the previous driest such
three-year combination in a record stretching more than 70 years.

It is also interesting to note that on many streams, the percent of
average diminishes downstream from the headwaters. Since these are
departures from average, the normal loss of water downstream is
already accounted for in these figures, so the implication is for
extra losses. I haven't heard an opinion as to why that should be
the case.

The continuing drop in the forecasts for the mainstem Colorado,
especially the inflow to Lake Powell, has been very interesting. The
March 1 forecast of 50 percent dropped to 38 percent on April 1, and
may drop further in the absence of any good storms. For just such
eventualities, the Colorado has four years worth of storage capacity,
and is maybe a year behind in the bank account, but again most of this
is in the two biggies, Powell and Mead, which are well downstream of
most source regions. The upper reservoirs do not have this luxury,
and anyway, there are a gazillion legal arrangements governing the
transfer of water from one way station to the next.

As far as I can discern, the Rio Grande is going to be the real center
of attention this summer. Streamflow projections have continued to
drop, and there are almost no prospects for relief. It's been hard to
find much snow below 11,000 feet, a very unusual circumstance for
early April. The delivery from Colorado to New Mexico will be very
low, the input within New Mexico will be very low, the reservoir
storage on the system is not very good, the delivery from New Mexico
to Texas will be low, the contribution from Mexico and the Rio Conchos
will be very low, population and demands are growing, the fish want
some water to live in, storage is not good, and there simply will not
be enough to accommodate all the interests.

I was told by some visiting snow surveyors from near Wolf Creek
Summit, on the upper Rio Grande, that given the unusual early peak,
and nearly clear water, that the maximum flow was considered to have
already occurred, and according to the compact, CO had thus met its
annual obligation to New Mexico, and the cross border CO-NM flow would
be dropped to its legal minimum of 40 cfs, something barely noticeable
on this river. The latest instantaneous flow figure I saw for the Rio
Grande was 13 percent of average. Many agricultural interests in the
San Luis Valley will receive no water, in many cases because the water
does not reach the bottom of the diversion structures. Snowplows were
recently ordered out to clear several inches of dust from the
highways. The extensive aquifer underneath this valley has dropped by
5 to 15 feet this year, representing about 300,000 AF of water.

There are interstate compacts and international compacts and treaties
with various parties along the entire length of this river, and those
are going to be exercised and tested in the fashion of a marine
training camp. A generous monsoon can help a tad, but we must wait
for next winter. On the whole western scene, this one has the worst
prospects, and the largest number of bad places it can go.

The Colorado scene has been getting plenty of attention, not much more
needs to be said there. Just as an aside, I recall sending out
something, mostly tongue-in-cheek, last fall sometime, that there was
some possibility that things could turn really serious in the
southeast portion of the mountainous part of the state, but that the
(unconditional) odds of that happening were not high. Conditioning
probably wouldn't have helped, because the main conditioning factor
would probably be our general ignorance. But, oddly enough that's the
way it turned out so far.

Similarly the Utah situation has been well described by Randy J, and
they are certainly some distance from bottoming out.

The Montana-Wyoming situation is likewise not that good, and plenty
has been said about that as well. The one little source of hope is
that their spring rainy season (Apr-May-June), if it materializes, can
make some difference. It's like being late in the evening, deep in
debt, but trying to get enough cash flow to get through the next poker
hand, and play one more time.

None of these things really totally snuck up on us, but understanding
and perception often comes in jumps rather than steady increments.
One thing that would really help immensely would be a much better
system for getting better quality live data into a comprehensive
tracking system. The problems in the northern Rockies, and in the
mountainous regions in general, show that even with all the disks and
CPU and internet connections, we are in a very primitive state in our
ability to rapidly paint an accurate picture with reference to
historical context, based on high quality and temporally homogeneous
information. This really needs to be fixed.

The winter as a whole has been about a degree above average (since Oct
1),
none of which has helped. The general effect has been to shorten
winter,
raise it up the slopes, get spring and vegetation and water wicking
going
early, not get as much water into the soil, and begin using it up
earlier.

On top of all this, I believe this is the only year I can remember
since I began working in western climatology issues back in 1982, that
every one of the western states has below average reservoir storage.
This territory is big enough and diverse enough that there is almost
always climatic "compensation" in water supplies and replenishment,
some areas up while other areas are down. (Of course, we can't ~do~
much with such compensation, because it cannot be redistributed on a
whim, and anyway that would entail the re-entry into Webster's of an
old phrase, "over my dead body.") The dipole in winter precip is the
biggest indicator of this, something tied in with ENSO and perhaps other
things too.

Haven't mentioned fire, but why bother.

All in all, this winter has set up significant prospects (but not a
guarantee) of widespread drought of a type not seen for decades. The
last major a really extensive, long-lasting drought in the West was the
drought in the 1950s, which affected mostly the Southwest. We have
had a bunch of smaller ones, on the Columbia, the Sierra Nevada, and
so forth, since then, but nothing really affecting more than 2 or 3 or
maybe 4 states at a time. It would not take much for a kind of
coalescence to link all the hot spots up into a western drought complex.
(Plus, this may become a medical term that we will all suffer from.)

I have a feeling we are further along this path than we have perceived
or are willing to admit. The signs are all over.

Kelly


_______________________________________________
Drought mailing list
Drought@ndmc.unl.edu
http://ndmc.unl.edu/mailman/listinfo/drought”

“4% humidity here in Flagstaff. Water restrictions are on for the city. Fire situation scary.”

“Just looked up the numbers for northern AZ area.

Live moisture running 80-90% and thousand-hour fuels in the mid single digits (6-8%).

For reference: kiln dried lumber runs around 12-13% moisture content. The three inch and larger woody debris are half that in Flag, so your forests are drier than a lumber yard.

Let's hope the SW gets the monsoons early.

Here in norcal things are close to average. We still have some roads closed above 6,000 feet. One of my favorite bike trails is still snowbound :(”