Category Archives: Climate

Do volcanic eruptions impact climate and weather?

There are some spectacular photographs and videos of the recent eruption of Calbuco in Chile. The impact of the eruption on our weather and climate depends on how explosive the eruption and how much sulfur dioxide is in the volcanic plume.

Eruptions can lead to cooler temperatures in the mountain’s vicinity. As the ash cloud enshrouds nearby regions, it will reduce the amount of solar energy reaching the surface and thereby reduce the daytime temperatures. Continue reading

Category: Climate, Phenomena, Weather Dangers

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What is permafrost?

Permafrost is ground that is frozen for at least two years. It remains frozen all year and contains plant material that has not yet completely decomposed.

Permafrost is mostly located in polar regions, though it also occurs in some high mountain tops where it is called alpine permafrost. There is no permafrost in Madison, though our ground does freeze in most winters. Continue reading

Category: Climate, Seasons

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How severe has this winter been?

Last year we experienced a persistently cold winter (December-January-February) that ended up being the coldest since 1979.

This year has been different. The Midwest Regional Climate Center is experimenting with what they are calling the Accumulated Winter Season Severity Index (AWSSI), which incorporates temperature, snowfall and snow depth to rate the severity of winter. Continue reading

Category: Climate, Meteorology, Seasons

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Is the ground temperature changing?

First, let’s consider air temperature.

The Wisconsin Initiative for Climate Change Impacts, or WICCI, analyzed data from 1950 to 2006, a 57-year period. Wisconsin has warmed during this period.

The observed warming since 1950 has been greatest in winter, with an average increase of 2.5 degrees across Wisconsin. Winter temperatures in northwestern Wisconsin have increased by 3.5 to 4.5 degrees. Continue reading

Category: Climate, Seasons

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How unusual is our roller coaster winter?

It doesn’t take an exceptional attention span to realize that this year’s cold season (starting in November) has been very changeable.

November was 6.1 degrees colder than normal, then December was surprisingly mild (5.8 degrees above normal). As of Thursday — mid-month — January has been 8.5 degrees below normal. Continue reading

Category: Climate, Meteorology, Seasons

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