Snow Is a Great Insulator

I'd like to share an observation regarding snow-cover. I placed a remote temperature sensor in a flowerbed last fall. It has become our favorite gauge of the outside temperature, since the digital display is on the base-unit inside the house. It is a very accurate ambient temperature sensor and proofed to be more believable than the big thermometer hanging off the garage outside west facing wall.

We had some lovely mild temperatures into December. I remember seeing a fly in the yard on December 1st, which I thought was very odd for Calgary. Our first snowfall in December was accompanied by mild temperatures. That dump of snow provided a very good insulating blanket for the big dip into the -20's & -30C. The remote sensor is about 3 inches above ground level with the moisture probe in ground. I didn't realize how much of a difference the snow cover makes. Very interesting. With 6" of snow cover and an ambient temperature of -30C, the remote registered -8C. With temperatures around -20C, the remote sensor registered -5C. In addition to snow insulating from the cold ambient air, the warm Chinooks were also affected. At +5C ambient, under the snow it was still -2C. Wow, what a difference. My not-so-hardy roses may survive this winter very well with the blanket of snow.

There are a number of remote weather devices available on the market. A couple of things to consider when shopping for one are: lithium batteries work better in extreme cold temperatures for the sensors; check the lowest temperature the device will register. Some unit specifications state the unit will register low temperatures to -39.5C. There are some units that are only good for -20C, so do check. Often retailers sell the base unit with one remote and do not offer extra remotes. We have 3 remotes with our unit (garage, backyard and front yard). A click of a button and I can check all 3 locations. I have a second unit which has a moisture probe and adjustable alarms for low and high temperatures. The base unit displays the temperatures, moisture level and low battery indication for the remote. This is a very cool gardening toy and handy in the greenhouse.

I certainly will be more diligent on shoveling the snow on the flowerbeds in the future. It not only provides future moisture, the insulating value is huge. The roses will have a fighting chance this year if the snow cover stays.

Some official info if you are interested: http://atlas.nrcan.gc.ca/site/...