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Winter’s thief
This week in January is normally the coldest in Missouri, with Columbians
digging through snowdrifts or dashing perilously down Sled Hill. But temperatures
are expected to be in the 60s today. So what happened to the cold? A little girl stole it. La Nina, which is Spanish for "little girl," is the name given
to a phenomenon in which deep ocean water rises to the surface across
the Equatorial Pacific, making it unusually cold for a 3,000-mile belt
from Peru to Tahiti. During La Nina in the United States, though, winters are warmer than
usual in the Southeast and cooler than normal in the Northwest. On the other hand, El Nino, which created blizzard-like conditions for
most of the Midwest a few years ago, is when Equatorial Pacific waters
are unusually warm. El Nino was named after Jesus by South American fishermen,
who noticed that the ocean would heat up around Christmastime. "We're experiencing a moderate La Nina right now," MU meteorologist
Pat Guinan said. "During La Nina, the jet stream tends to be farther
north. It all has a kind of domino effect on air masses all over the world."
Guinan described the jet stream as a river of air flowing 30,000 feet
up. The jet stream is currently moving evenly from west to east, without
curving either north or south for the most part. "The jet stream is keeping all the cold air locked up in Canada
and unable to give us cold spells this winter," Guinan said. "We've
had an above-normal winter since Nov. 1. It's been an above-normal winter
for most of America." Guinan did point out that during La Nina, temperatures sometimes were
below normal in the winter, dipping below zero. This winter, however,
has remained unusually warm for the last 75 days. "It looks that residential heating bills in Columbia are running
about 12 to 15 percent lower than this same time last year, from Dec.
1 to Jan. 1," said Mike Cleary, supervisor of media relations for
AmerenUE. Humans, however, are not the only ones benefiting from the unseasonable
warmth. "There are several insects that gave us problems last year during
the mild winter that I expect would give us problems this year,"
MU entomologist Wayne Bailey said. "The insects may or may not cause
us more problems in spring, but we expect that they should have higher
populations." Bailey said several major pest species spend the winter in Columbia.
The stinkbug and the southern corn rootworm target corn, while the bean
leaf beetle and the cereal leaf beetle afflict soybean and wheat crops.
MU entomologist Bruce Barrett noted that harsh winters do not necessarily
lead to low springtime pest populations. "Conversely, we've had mild winters where we expected large pest
populations, and they haven't occurred either," Barrett said. "What
may be detrimental to one insect may not be harmful to another species."
Mites, for instance, thrive in hot, dry weather, and are found on vegetables
and ornamental plants, Barrett said. On the other hand, white grubs, that
target lawns, have a harder time moving through the soil and laying eggs
when the weather is not moist and humid. "Unfortunately, we are not very good at determining which insect
populations will be largest in spring," Barrett said. "Predicting
insect population density solely on the type of winter, harsh vs. mild,
is hardly an exact science." "What really kills insects sometimes is not how cold it is, but
how quickly it changes to cold weather," Bailey said. "It helps
that there is no snow cover to insulate them. We'll get more mortality
that way." Bailey added that many pest insects are migratory, "so it doesn't
necessarily matter what happens here." But while insects may benefit from the mildness of this winter, peach
trees may not. "We're going to need a lot of chilling hours before the peach trees
come out of dormancy," said Kevin Johns, president of the Missouri
Peach Merchandising Council. "But as long as it's cool in the night,
it's all right." The unusual warmth Columbia is experiencing may be ominous to some. Still,
the scant two-tenths of an inch of snow Columbia has received so far could
bear fruit of a different kind. The current record low for Columbia is
4 inches of snow, set in the winter of 1982 to 1983, an El Nino year.
"We have a run for the record," Guinan said. |