Perilous
Times
Massive dust storm closes highways in Idaho
SALMON, Idaho | Thu Dec 29, 2011 9:27pm EST
(Reuters) - A dust storm churned by winds of up to 50 miles per
hour forced a 20-mile closure of an interstate in Idaho on
Thursday, and highway officials scrambled to divert thousands of
motorists near Idaho Falls.
Dirt blowing off cropland drastically reduced visibility for much
of the day along a portion of Interstate 15, the north-south route
that runs from California to Montana and intersects Salt Lake City
and Las Vegas.
The early morning closure ordered by the Idaho Transportation
Department was expected to extend into the evening hours and go
into effect again on Friday night, when a second Pacific storm
front was forecast to unleash high winds.
State highway officials said it was rare for a storm this time of
year to sweep large clouds of dirt across the Upper Snake River
Plain in the high desert of eastern Idaho.
"This may be the first time we have ever closed the interstate for
a dust storm in December," spokesman Bruce King said.
The closure affected a segment of the interstate north of Idaho
Falls that serves an average of 21,500 vehicles a day. Motorists
were detoured along lesser-trafficked federal highways east of the
Snake River.
Blowing dirt occasionally sweeps across the area in the spring and
fall when crop fields are tilled. But snow typically prevents a
dust-up in the winter.
Thursday's dust storm followed two similar but somewhat less
unusual events in November that caused a closure of I-15 near
Idaho Falls.
Whirlwinds of dirt the Friday after Thanksgiving turned day into
night along that stretch of interstate, causing multiple
accidents. The state had to remove abandoned vehicles and clear
piles of sediment before reopening the route.
A high-pressure ridge parked for weeks over the Northern Rockies
has shielded the region from Pacific storms that normally blanket
the ground with snow, said Mike Huston, meteorologist with the
National Weather Service in Pocatello.
That ridge has since weakened, opening the way for fronts bringing
the high winds behind Thursday's dust storm and one predicted for
Friday, he said.
(Editing by Steve Gorman and Cynthia Johnston)