By Thom Luloff, Master Gardener in Training
Snow after Christmas has a public relations problem. It blocks driveways and arrives just in time for the morning commute. But ecologically speaking, snow is a quiet hero; less frozen nuisance, more life-support system.
Freshly fallen snow is light and fluffy, packed with tiny air pockets that make it an excellent insulator. This airy layer acts like a thermal blanket, keeping soil temperatures relatively stable even when the air above plummets. Beneath it, plants are spared damaging freeze–thaw cycles, roots avoid frost heave, and soil microbes continue their slow, essential work (Pauli et al., 2021; Saccone et al., 2013).
As snow ages, it settles and compresses into denser layers. Below these compressed layers is a gap between the snow and soil, the subnivean zone—a hidden world of tunnels for voles, mice, shrews, and overwintering insects. Stable snow layers mean stable winter habitat for these creatures which directly influences survival migrating birds and awakening mammals (Pauli et al., 2021).
Snow also plays the long game. Acting like a frozen reservoir, it stores winter precipitation and releases it slowly during melt. This gradual release recharges groundwater, sustains streams, and prevents spring flooding. Crucially, snowmelt fills ephemeral pools—temporary wetlands that appear just long enough for frogs, salamanders, and invertebrates to breed before drying out. These pools are biodiversity hotspots, and many amphibians depend on them entirely for reproduction (Brooks, 2004).
Climate change, however, is rewriting snow’s script. Warmer winters mean thinner, more variable snowpacks, frequent mid-winter melts, and icy crusts instead of fluffy insulation. These unstable layers expose soil and roots to harsh temperature swings, collapse subnivean habitats, and increase winter mortality for small mammals and plants alike (Saccone et al., 2013; Pauli et al., 2021). Reduced snowpack also means less spring meltwater, shrinking ephemeral pools and compressing breeding windows for amphibians.
In short, inconsistent snow is not just inconvenient; it’s ecologically disruptive. When snow comes late, melts early, or freezes into ice instead of insulating layers, entire food webs feel the impact. And we are feeling it this year.
The next time snowflakes fall, take a moment. That squeaky, shovelled nuisance is buffering ecosystems, storing water, protecting roots, and quietly setting the stage for spring. Snow may be cold, but for nature, it’s doing some very warm-hearted work.
References
Brooks, R. T. (2004). Weather-related effects on woodland vernal pool hydrology and hydroperiod. Wetlands, 24(1), 104–114. https://doi.org/10.1672/0277-5212(2004)024[0104:WREOWV]2.0.CO;2
Pauli, J. N., Zuckerberg, B., Whiteman, J. P., & Porter, W. (2021). The subnivium: A deteriorating seasonal refugium. BioScience, 71(8), 820–831. https://academic.oup.com/bioscience/article/71/8/820/6213245
Saccone, P., Morin, S., Baptist, F., et al. (2013). The effects of snowpack properties and soil frost on plant and microbial communities. Ecology, 94(7), 1617–1630. https://esajournals.onlinelibrary.wiley.com/doi/10.1890/12-1327.1
Photo Credit: AI generated Image
The Peterborough & Area Master Gardeners 