Use of the Forest

Public use of Saginaw Forest is encouraged. Rules for the public's use include (but are not limited to):

Wednesday, March 21, 2012

The winter that never came, and what it might mean

Well, I pointed out back in January that the winter - at least the version one could expect in Ann Arbor, MI - wasn't actually here. Then, through February, we waited for winter to come, and - other than a couple of dips in the temperature and some snow that lasted a couple of days - we continued to remain stubbornly above freezing on most days.

Now, in March, the trees are trying to catch up with the temperatures that closer to what is typical of late June than anything close to what we would expect in March, let alone April (we could reasonably expect 82F/28C temperatures in May, but they are historically rare). In short, the temperatures we are experiencing in Ann Arbor are presently CONSISTENTLY SHATTERING all historical measurements (all the days from March 14 through March 21, 2012 have broken the previous high-temperature record, and the current forecast expects that March 22 and 23 are also going to be record-breakers, which - if true - means that there will be nine full days of record-shattering temperatures).

"But it's not TOO hot," and, "I LOVE this kind of weather," I hear some people say. Well, true: temperatures of 70-80F are quite comfortable, and it's no surprise that we'd love the temperatures that we (likely) evolved to thrive in. Such high temperatures, do, however, bring drawbacks.

The insects are also loving it - I've been having mosquitoes in Saginaw Forest for the past two weeks, and the moths and mayflies are starting to emerge. The frogs, too, are quite happy, singing up a storm in the evenings, but their choruses are already starting to die down. I wonder how long the summer temperatures will hold this year: will we remain (relatively consistently) above 70F from now to late September? Will we again get up past 100F in July? Will we again have a rain-stressed year? (I also wonder if the weather will suddenly remember that it's only mid-March and dip back into the "average" temperature range of lows in the low-30s and highs in the mid-40s.) For Saginaw Forest, such changes could spell - if continued over years - a major shift in the types of trees that continue to thrive in the hotter and drier weather. If - instead of spring snowmelt (which we didn't really get this year) and long, soaking summer rains - we have little snowpack and get only sharp and harsh spring and summer downpours, the little creek on the property will likely erode away the banks ever faster, the water table will likely drop, since there is little opportunity for saturation to occur, and - again - the trees will change. After several decades of a warmer and drier climate (one which is characterized by shorter and wetter rain storms), the forest will likely come to look increasingly like northern Georgia than southern Michigan... something that does give me pause.

I know that this lack of a winter doesn't necessarily mean that climate change is upon us. The winter continues to be a bitterly cold one in Europe, after all. However, if this year is anything to use to predict some likely occurrences in a warmer climatic future, then I hope that people are paying attention. What starts as "nice temperatures" turns into "bad weather" as the high level of heat energy in the atmosphere brings about earlier and more intense storms than what our experience has led us to expect. In the Ann Arbor region, this meant a tornado touching down in Dexter, combined with intense rain (over 1" of rain in 1 hour at Ann Arbor airport) and hail, which caused flooding in Ann Arbor (as both storm and sanitary sewers became flooded beyond capacity), massive erosion along rivers (as they "endeavored" to accommodate the massively increased flows of water), and felled trees (thus knocking out electricity for thousands as well as destroying more property).

Looking more regionally, we have seen the start of one of the earliest tornado seasons on record. According to
In the U.S., tornado season tends to move northward from late winter to mid-summer. In Southern states, tornado season is typically from March to May. In the Southern Plains, it lasts from May to early June. On the Gulf Coast, tornadoes occur most often during the spring. And in the Northern Plains, Northern states and upper Midwest, peak season is in June or July.
As of March 20st, the number of tornadoes in the US reached 285, which is almost tied for the most tornadoes on record by NOAA. (As a contrast, in a year that is at the 50th percentile, we wouldn't reach 285 tornadoes until roughly the end of April.) When looked at through the light of all the record temperatures, it's not too surprising that so many tornadoes are happening, but it's also very little consolation that warmer temperatures means better times.

No comments:

Post a Comment