Two sensors have been collecting data for a bit over two weeks.
It is quite remarkable how little the temperature underground changes. Now that we are in mid-December the temperature at one foot ground depth (blue line) have steadily dropped from about 6-6.5C to 4.5-5C. This winter was mild so far as can be observed by the above ground (red line) temperature staying well above freezing from noon through early evenings most days.
So far there is no concern what so ever about tree roots access to liquid water.
The next interesting step is 3 inches of snow that covered the ground today. The air temperatures are expected to stay below freezing next few days.
Looking great. I thought that with the Iowa winters, the temps would've dropped below zero by now.
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I checked the official data and it reads as follows:
Delete“ Winter Summary: Temperatures for the three winter months of December, January and February (DJF) averaged 21.2 degrees or 0.9 degree below normal while precipitation totaled 2.82 inches, 0.49 inch below normal. Winter 2021 ties 1995 as the 63rd coldest winter with a colder one occurring in 2018. In terms of precipitation, it ties 1966 and 1985 as the 52nd driest; 2013 was drier. The statewide average snowfall was 32.2 inches, 9.4 inches above normal, making it the 12th snowiest winter in 134 years of records with 2018-2019 experiencing more snow.”
So, slightly colder than average. However, this what it says about February, temperatures in Fahrenheit:
“ Frigid temperatures blanketed the state for a good portion of the first weeks of February due to an Arctic air outbreak from a bulge in the Polar Vortex. The Polar Vortex is a large low pressure system over the Arctic basin that dams off frigid air from the mid-latitudes. When the vortex weakens and begins to wobble, meanders (dips) form that allow bulges of cold air to intrude into the Midwest. Typically after a burst of Arctic air, warmer than average temperatures follow from west to east over the following several days. While there was a rebound in the statewide average temperature behavior given warmer than normal temperatures at the end of the month, average temperatures for February were anywhere from eight to 16 degrees below normal. The coldest period of the month was between February 7th and 16th when the average temperature was -5.2 degrees, 27.2 degrees below normal. Temperatures did not rebound to normal until the final eight days of February, where the average temperature for the period was a degree warmer than climatology.”
Very cold February, above average December and January.
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DeleteIt was an average winter with a few cold spells below -20C but nothing extraordinary. I bet the average would even be above normal. Too bad sequoias don’t care much about the average and care about solid frozen roots. Other species of conifers are more forgiving l.
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