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News from the Keweenaw Peninsula Posted March 7, 2002 Text © 2002 Katie Alvord Photo © 2002 Keweenaw Now

Michigan registers warmest winter on record

By Katie Alvord

HOUGHTON -- A few days before the arrival of March with some near-blizzard conditions, Marquette climatologist Kevin Crupi thought this winter's Upper Peninsula temperatures might set a new record for warmth.

Crupi was close. As the meteorological winter ended last Thursday, average temperatures at National Weather Service (NWS) headquarters for the Upper Peninsula, where Crupi works in Marquette, fell just under the record. But for the state of Michigan as a whole, preliminary numbers do now indicate this was the warmest winter ever measured. And temperatures collected at Michigan Technological University have yielded well-above-normal monthly averages since November.

Swedetown Creek meanders along the Maasto Hiihto Ski Trail in Hancock. Weather observers say warmer temperatures this year have resulted in lower snowpacks despite higher snowfall in some areas. (Late January 2002 Keweenaw Now photo)

"It's certainly been one of the mildest winters I've seen since moving up here 25 years ago," says Jim Carstens, a retired MTU professor emeritus who tracks the weather data at MTU for the NWS.

The MTU measurements include average high and average low temperatures for each month. As of November 2001, Carstens says, the temperature data started "getting kind of funny." That month proved to be the warmest November measured in nine-plus years of record-keeping at MTU, and by a wide margin. November's average high of 51.2 degrees was nearly 11 degrees warmer than the 40.8 degree nine-year average for the month in that location. The average highs and lows at MTU have been above normal each month since then (see table).

Lake Linden meteorologist John Dee confirms that this winter's weather has been marked by higher temperatures, but also higher snowfall in some locations. The warm temperatures, though, have caused much more melting of snow, especially in low areas and near Lake Superior, resulting in lower snowpacks.

"That's been the main theme of this winter," says Dee.

At his Lake Linden station, Dee has measured slightly higher than average snowfall so far this season. As of the end of February, he'd measured 184 inches of snowfall, compared to a fifty-year average of 176 inches by that date at the nearby Houghton County Airport.

Winter 2001-2002 mild across Midwest

As far as temperatures go, this winter has been a record mild one across much of the Midwest according to Jay Lawrimore, chief of the Climate Monitoring Branch of the National Climatic Data Center (NCDC) in Asheville, North Carolina. Preliminary calculations show that ten states from the Plains to the Northeast -- including Michigan, Wisconsin and Iowa -- have had their warmest winters on record. Minnesota registered its second warmest December through February. For the whole country, this ranks as the fifth-warmest winter on record, says Lawrimore.

Climate and weather agencies define December through February as meteorological winter, but if they throw November into the mix even more records tumble. NOAA (the National Oceanic and Atmospheric Administration, the parent organization of the NWS and the NCDC) has already announced that the three months of November 2001 through January 2002 broke a record for the warmest such period ever measured across the entire United States. And the last four months have been the warmest November through February on record in Marquette, with the average temperature hitting 27.2 degrees.

That's three degrees warmer than the previous record for those four months, a significant difference when many weather records are broken by tenths of a degree.

"That speaks volumes about how warm it's been here," says Crupi.

Crupi reports that the Marquette NWS station's average temperature for the three winter months, December through February, was the second highest on record, at 23.0 degrees. The warmest average winter temperature in Marquette, 23.4 degrees, occurred during the El Niño winter of 1997-98.

This winter is "in keeping with the trend since the late nineties of very mild winters" in our region, says Crupi. Of the last five winters here, all but the 2000-2001 season have fallen onto the list of the region's top six warmest winters.

In general, Crupi adds, our warmer winters have also tended to be more snowy. This year, Marquette has measured one of its snowiest winters, and February set a record for the snowiest month ever. A total of 91.9 inches fell last month at the Marquette station, which is located about 800 feet higher than the Lake Superior shoreline in Negaunee Township.

At MTU, on the other hand, snowfall is running below normal at 121 inches so far this year, when the average total for the season is 165 inches at that location.

Like John Dee, Crupi observes that this winter's higher temperatures have contributed to lower snowpacks particularly in low areas and near shorelines, such as MTU's location.

The warmer temperatures seen at MTU are part of a trend observed since that weather station began data collection in 1993.

MTU's Carstens has also witnessed warm temperatures this late fall and winter.

"There's a definite warm-up that's occurred just over the last nine years," he notes. "The trend is a gradual increase in both high and low average temperatures."

Carstens hesitates to say whether this might indicate climate change.

"It does seem to support the idea, and you can certainly make an argument for that," he says. "But it's a very debatable subject, and nine years is a very short period on which to base any conclusions."

John Dee agrees that whether or not this winter's "phenomenally warm" weather has to do with climate change is hard to pin down definitively.

"It's possible that the warm temperatures we've seen are part of a bigger-picture warming of the atmosphere, but that's a tricky call," says Dee.

Experts note trend toward global warming

The NCDC's Lawrimore notes a worldwide trend toward warmer temperatures.

"You never really can look at a single season or single weather event and say it's due to climate change," Lawrimore says. "But, having said that, we have seen a trend toward warmer temperatures in the U.S. and around the globe in the last century."

Lawrimore adds that "the data show a significant amount of warming as well as other changes that are consistent with what you'd expect to occur in the climate when you have an increase in carbon dioxide and other greenhouse gases."

The International Panel on Climate Change (IPCC), an international body involving thousands of scientists who have studied and reported on these issues, has found that at least a portion of the warming is due to human activities, Lawrimore explains. At NOAA, he says, "we don't differ from that opinion."

Average temperatures, he states, have gone up about 1 degree Fahrenheit in about the last hundred years. And in the last 25 years, average temperatures have risen at a rate that's equivalent to three times faster than that.

Research by Elise Ralph of the Large Lakes Observatory in Duluth suggests that Lake Superior, too, has warmed over the last century, by about 0.5 degrees Centigrade. MTU Associate Professor of Chemistry Sarah Green, who works with Ralph in the KITES project (an interdisciplinary study of the Keweenaw Current in Lake Superior), points out that "even a slight warming of the lake could change our weather" locally. She adds, "Lake Superior acts as a huge local heat reservoir. In the long term, warming of the lake could also delay the onset of winter weather because it will take longer to cool the surface water in the fall."

A pattern of delayed winter onset does seem to have occurred this year. November set a record for warmth, December saw little snowfall until just before Christmas, and, says John Dee, "the whole month of January was spring-like, with snow and periods of melting." 

The beginning of March this last weekend saw the most winter-like weather we've had all year, he observes.

Despite the chilly first few days of this month, forecasters do expect temperatures to warm again. Long-term forecasts predict above-normal temperatures for March overall, as the jet stream shifts into a position that will bring more mild weather to the U. P.

And there may be more warmth in the region's future. Scientists predict the possible return of El Niño later this year. This condition of above-normal temperatures in the eastern equatorial Pacific Ocean typically brings warmer, drier weather to the Upper Midwest. By this summer, observers expect to know whether El Niño will actually materialize, and if it does, how strong this particular El Niño might be.

Learn more about the author of this article, guest writer Katie Alvord.

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