The dazzling frost that transformed Calgary into a sparkling winter landscape is beginning to melt, but its departure leaves behind significant advantages for the local flora. Contrary to what some may think, the thick coatings of ice and frost are not damaging to trees and plants; they serve as a vital protective shield.
Nature's Insulating Blanket
Kath Smyth, a horticulturist with the Calgary Horticultural Society, emphasizes the protective role of this winter phenomenon. "The more hoarfrost and rime that we can get on them, the better off the plant is," Smyth stated in early January 2026. She explained that without this frosty layer during extreme cold, the tips of deciduous trees could die back.
The frost acts as an excellent insulator, safeguarding the delicate new buds that have already formed on some trees. Smyth noted a personal observation: "This is probably the first time in a January that my climbing rose is still supple all the way to the top of the trellis." The humidity provided by the frost is a key benefit in Calgary's typically dry winter air.
Moisture for a Thirsty Landscape
The benefits extend beyond the branches and down into the earth. Smyth highlighted that the additional moisture is a boon for the soil, which is especially crucial following an exceptionally dry autumn. As temperatures warm and the frost begins to dissipate, the moisture slowly seeps into the ground, helping to replenish it.
This natural irrigation should lead to noticeable positive effects for gardeners in the spring, Smyth said, barring an unusually dry March. She expressed hope for consistent snow cover, noting that the current weather patterns, unimpeded by the mountains, are putting the region in "pretty good shape."
Rime Ice vs. Hoarfrost: What's the Difference?
While they look similar, the glittering coatings seen in Calgary are primarily rime ice, not hoarfrost. Alysa Pederson, a meteorologist with Environment Canada, explained the distinction. Rime ice forms when supercooled water droplets in fog or clouds freeze instantly upon contact with cold surfaces like trees, roads, or fences.
"They're so small that they're able to actually be below zero degrees, but because they're so pure in themselves, they don't actually have anything to freeze on," Pederson said. A slight wind is also necessary to move the fog and allow for continuous deposition of these tiny droplets, resulting in the characteristic feathery texture.
This natural event, witnessed by Calgarians over the weekend of January 3-4, 2026, provided more than just a beautiful spectacle. It delivered a vital, protective layer of insulation and moisture, offering a hidden boost to the city's urban forest and gardens that will pay dividends in the coming seasons.
