Low rainfall could mean big problems
Doughton; The News Tribune
Western Washington is basking in a rare spell of golden fall weather,
but too much of a good thing could turn nasty, say the experts who
track the region's water.
The unusually dry weather already is taking a toll on salmon. If
it persists much longer, it could cause problems for water supplies
and power generation, U.S. Geological Survey hydrologist Bob Kimbrough
"If it would continue to be dry, we could have the potential
to have an even lower runoff than two years ago," he said.
Two years ago, the region was hit by one of the worst droughts in
the past century, driving the power system into crisis and leading
to huge electricity rate increases.
Power and water managers say it's far too early to panic. A normal,
wet November and December and a healthy winter snowpack could easily
erase the early fall water deficit.
But with a moderate El Niño blossoming, this winter has the
potential to be warmer and slightly drier than usual, said Brad Colman,
science officer at the National Weather Service Seattle headquarters.
"We don't know fully what's going on," he said, "but
it's certainly consistent with El Niño."
The winter weather pattern should become apparent by late November
or early December, Colman said.
"It's too early to say much - except go out and enjoy the good
weather while it's here."
The Weather Service's climate models are predicting at least another
nine days of clear, dry weather. After that, the model suggests rain
may reappear - but last week, the same model was predicting a soggy
Halloween week, Colman cautioned.
Whatever happens over the next months, the past month was one for
the record books.
With a scant 0.66 inches of rainfall, it was the second-driest October
on record at Sea-Tac Airport.
The four-month period from July 1 to Oct. 31 was the driest ever at
several spots across the state, including Sea-Tac, Bellingham and
the Washington coast. In a normal year, slightly more than 7 inches
of rain falls at Sea-Tac between July and October. This year's total
was 1.76 inches.
The lack of rain is shrinking rivers and streams to record low levels
for this time of year, stranding migrating salmon and forcing closure
of popular fishing areas, Kimbrough said.
From an office in downtown Tacoma, he and his co-workers monitor stream
and river flows at 250 sites across the state. At most of those sites,
automated stream gauges record measurements several times a day and
beam the information to the computerized USGS network.
The data are displayed as colored dots on a series of maps: Green
and blue for streams where flows are above normal; reddish hues for
those where flows are lower than normal - including those hitting
new daily lows.
In mid-September, the red dots began proliferating, and the situation
is only getting worse, Kimbrough said.
October is usually one of the region's reliably rainy months, added
USGS hydrologist John Vaccaro.
"Dry Octobers are very rare," he said. "There have
probably only been three or four in the last hundred years."
Last winter's snow and rain never completely replenished the groundwater
lost in the 2000-2001 drought, which seems to be aggravating the current
low stream flows, Vaccaro said.
"It can take several years to recover," he added.
On Thursday, the stream flow in the Puyallup River, near Orting, was
132 cubic feet per second, less than one-fourth the normal level of
The Nisqually River was flowing at 109 cfs, compared with the normal
level of 586 cfs.
The biggest impact of the low flows has been on the north coast of
the Olympic Peninsula, where some flows are one-tenth normal, and
migrating chinook salmon are fighting to make their way up rivers
with barely a trickle of water, said Craig Bartlett of the Washington
Department of Fish and Wildlife.
Sandi Doughton: 253-597-8516
SIDEBAR: A DRY SEASON
This year: 0.66 inches
Normal: 3.23 inches
Record low: 0.31 inches, 1987
This year: 1.76 inches, a record low
Normal: 7.01 inches
Previous record: 1.90 inches, 1987
Data from Sea-Tac Airport, U.S. Weather Service