Fairbanks melting season brings a lot of hazards. Learn why snow height already decreases at temperatures below the freezing point. Read what happens in Fairbanks when finally daytime temperatures exceed the freezing point.
- Snow in Interior Alaska and Its Impacts
- Weather Differs from Climatology
- How Does Snow Height Decrease without Melting?
- Snow Metamorphism Prior to Onset of Snow Melt
- Meltwater Clogs the Drainage Systems
- Rubber Boots Are A Must-have
- The Snow Metamorphism and the Dirt
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Snow in Interior Alaska and Its Impacts
The snow often leads to closure of the Steese Highway at Eagle Summit for some time in winter. As a result, people living north of this point loose their road access to Fairbanks. Consequently, they depended on subsidence lifestyle, what they have in storage, and supply flown in by small aircraft landing on skids.
At the beginning of the melt season, snow piles up man-high along the roads and streets; despite the Department of Transportation hauls snow in trucks to places outside of the city limits after each winter snowfall.
Weather Differs from Climatology
The normal annual snowfall for the Fairbanks North Star Borough amounts 61.6 inches (156.464 cm). However, in some years, there can be much more (e.g., winters 2016/17, 2020/21, 2021/22) or much less snowfall!
Snow Vanishes Visibly in March without Snowmelt
Typically, March is the driest month the Interior with respect to precipitation (see diagram above) and cloudiness. Therefore, March provides the best chances to watch the aurora.
Despite temperature rarely go above the freezing point, snowheight decreases due to snow metamorphism.
How Does Snow Height Decrease without Melting?
Some of the decrease in height is related to settling due to gravity. Furthermore, the low relative humidity leads to sublimation of snow. In addition, water-vapor transfer occurs within the snow-pack because the saturation-vapor pressure over concave surfaces is less than over convex surfaces. As a result, the sharp edges of snowflakes sublimate at vapor-pressure values that still allow water-vapor to deposit on concave surfaces.
Consequently, dendrite-like crystals morph into hexagonal plates, and eventually, at the end of the snow season, ice spheres of about two mm (~0.08 inches) in diameter (see photo above). During this process, the snow density increases, while snow volume and depth decrease. Recall, density is mass per volume.
Meltwater Clogs the Drainage Systems
Once temperatures exceed the freezing point during daytime, snow-melt sets on. However, because the drainage system is still at temperature below the freezing point, the melt-water freezes upon entering. Consequently, the drainage system clogs up, and huge puddles form all over town. Of course, gutters have the same fate. Water drops from the roofs, sometimes building long icicles.
Streets and driveways turn into a mix of snow and water and/or great puddles (see video). Unpaved roads turn into mud.
At night, temperatures go below freezing, and water freezes. Areas may turn into black ice causing slipping hazard. Recall I broke my arm, and had to deal with that injury the Alaskan way during lockdown.
Rubber Boots Are A Must-have
Because of all the water, rubber boots are in order. However, rubber conducts heat very easily. Therefore, you loose body heat fast, i.e., your feet get cold in no time. Therefore, people wear double socks in their rubber boots, but light clothes.
Alaskans who can afford it have It Legacy Xtratuf. These boots are insulated. These boots are so It that brides even take their Xtratuf to their outdoor weddings. Unfortunately, these boots have no high heels. Therefore, they are not my statement heels shoes for breakup.
Snow Metamorphism and the Dirt
Along the streets, the snow piles turn gray or even black from dirt and gravel that remain in the snowpack when the water runs away.
The melting season brings out not only gravel (used to roughen the roads during winter) or seeds and needles that fell off the trees. It also brings out all the lost mittens, scarves, candy wraps, plastic shopping bags, masks, trash bags fallen off from pickup trucks, and whatever people disrespectfully threw away during winter.
More on Alaska permafrost at the links.
Dingman, S.L. (2021) Physical Hydrology. 3rd edition. Prentice Hall.
Fröhlich,K., Mölders, N. (2002) Investigations on the impact of explicitly predicted snow metamorphism on the microclimate simulated by a meso-β/γ-scale non-hydrostatic model. Atmospheric Research, 62, 71-109, doi:10.1016/S0169-8095(2)900005-4.
Photos of me: G. Kramm
Photos of snow, diagrams, video: N. Mölders
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