A Warm Winter Means Low Waters
The water level of Lake Superior is likely to fall to 4 to 6
inches below its average this winter. Mid-winter that put the level at
about 601 feet above sea level (how it is measured).
Lake levels rose in 2005, but a few elements conspired to
lower the levels again, according to a U.S. Corps of Army Engineer
hydrologist and meteorologist.
“Because it’s been so warm this winter, that snow hasn’t been
what it was in the past,” says meteorologist Keith Kompoltowicz. But,
he adds, “lower water levels this year are mostly due to the dry
conditions in summer.”
Hydrologist Carl Woodruff says that a winter lacking ice
cover adds to the problem. Major evaporation off the lake’s 31,700
square miles of surface area comes in fall when air temperatures drop
but the water remains (relatively) warm. Without ice in winter,
evaporation continues throughout that season.
Lake-effect snow, by the way, does not raise lake levels because the snow comes from the lake itself.
Lake Notes
 The
2005 season (March 2005- January 2006) waterborne commerce through
Duluth-Superior totaled 41,679,992 metric tonnes, a 1 percent increase
from last season and the port’s highest tonnage level since 1979. Coal,
the highest cargo, totaled 18,772,260 tonnes. Iron ore and grain are the
other top individual cargoes.
In Thunder Bay, the 2005 season total was 8,200,674 metric tonnes down
from last year’s 8,549,598 total. The main cargo was grain at 5,876,577
tonnes for the season. Other top cargos were coal and potash.
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