America is certainly suffering the effects of flooding
this spring and while we have no large-scale disaster such as that
currently plaguing the Mississippi Valley, the West has its own
flooding problems. As I look out my window at the Bitterroot
Mountains I see a solid mantle of white, a scene more likely noted
in March rather than May. After a cold, wet spring that inhibited
the melting of that snow and even added to it, the Salmon River has
finally risen with runoff.
The West has experienced a decade of “precipitation
deficits,” if not outright drought, so this past winter saw an
embarrassment of riches for skiers and other winter recreationists.
Snowpacks in the Northern Rockies, Pacific Northwest, and the
Sierra Nevada in California are running 150-200% of average. Here
where I live in Idaho, the Salmon Basin is 155% of normal, which is
actually a low number. Farther south, the Portneuf River Basin
above Pocatello sports an amazing 286%. These numbers promise at
least minor flooding regionwide. But if the weather suddenly gets
hot or rainy, it will be disastrous.
According to a recent story by AP, climatologists are
pointing to this year’s strong “La Niña,” in which cooler water in
the Equatorial Pacific Ocean causes wetter-than-normal winters in
the Pacific Northwest, California, and Northern Rockies, and drier
conditions in the Southwest. New Mexico, for instance, is suffering
an early fire season with over 300,000 acres already scorched. The
snowpack there along the Rio Grande is only 72% of
average.
The numbers are extraordinary. Loveland Ski Area west of
Denver broke its annual snowfall record of 572 inches (49 feet) set
in the winter of 1995-‘96. Snowbird Ski Resort near Salt Lake City
also broke its own record with a massive 711 inches (as of three
weeks ago), which is 59 feet. AP tells us that the resort plans to
remain open until July 4.
The latter indicates huge snowpacks averaging over 200%
along Utah’s Wasatch Front, which spells flooding woes for
metropolitan Salt Lake City. These snowpacks are even higher than
those seen in 1983 when City Creek flooded parts of downtown.
Interstate 80 was closed and the Great Salt Lake lapped at the
runways of Salt Lake International Airport. This year sandbagging
has been done earlier throughout the area.
The snowmelt in the Colorado River this year has caused
the U.S. Bureau of Reclamation (BuRec) to release 3.3 million
acre-feet of water from Lake Powell to Lake Mead, thus raising it
23 feet. That flow itself is 14 times the amount of water used in
Las Vegas last year. Metro Las Vegas was in a drought with
impending water restrictions as recently as last fall. “I’m
delighted, absolutely delighted,” Southern Nevada Water Authority
general manager Patricia Mulroy told AP. BuRec is draining
reservoirs throughout the West, as it seeks to move “storage” from
one to the next to better handle the snowmelt. Palisades Reservoir
sits at a mere 11% of capacity after water was sent downstream to
other Snake River reservoirs in anticipation of the big snowmelt
soon coming from the upper Snake drainage, notably Wyoming’s Teton
Range and the southern reaches of Yellowstone National
Park.
The major problem regionwide is that a cold April has
passed without snowmelt. Usually about 25% of
the snowpack melts before May 1, but not this year. This means that
a substantial warmup, or what meteorologists euphemistically call a
“rain event,” could trigger disastrous flooding, degrees of which
are inevitable. In Montana, for instance, the last big flood year
was 1997, when the Yellowstone River (the last great undammed
Western river) inundated parts of Livingston and other towns
downstream. That scenario is likely again this
year. Already the Yaak River in northwest
Montana, the Clark Fork downstream from Missoula, and the
Bitterroot River flowing from the south through its eponymous
valley toward Missoula are at flood
stage.
In California the Sierra Nevada snowpack is so bountiful
that Central Valley Project irrigators will have 35% more water
available to them this year than last. The snowpacks average 159%
down to 127% north to south along the mountain
range. The higher peaks around Lake Tahoe
accumulated over 60 feet this past winter. Again, a fast warmup
could inundate valley towns as in flood years past.
The West doesn’t flood on the scale of the South. And
considering that ongoing aridity is our normal state of nature,
we’ll take the bad with the good. It’ll be a nice green
summer.
