Performance and output

Snow loss estimator, Mountain West

Enter your snowfall, elevation, snow type, and how often clear skies follow storms. Get an annual kWh and dollar loss estimate built for mountain climates.

Your system and winter

1 Project details Optional
Shown on your exported report. Leave blank to skip.
2 Your system
Use your system's rated annual output before any snow loss.
Find this on a recent utility bill.
3 Your winter conditions
Denver averages around 60in, Salt Lake City around 55in, mountain resort towns often exceed 200in.
Steeper tilt sheds snow faster. Mountain roofs often run 30 to 45 degrees.
Higher elevation brings colder baseline temperatures that slow natural melting.
Dry powder slides off panels far more easily than wet, sticky snow.
4 Sun exposure and upkeep
Strong post-storm sun at altitude can melt snow off panels quickly.
More clearance under the panels lets slid snow fall away instead of piling up.
Manual or heated clearing recovers output that would otherwise sit under snow.

How it works

Four steps to a snow loss number

Step 1

Look up your snowfall and elevation

Mountain snowfall varies widely over short distances, so use your specific town's average rather than a regional figure. Pair this with the altitude impact calculator to see elevation's separate effect on output.

Step 2

Identify your typical snow type

Interior mountain ranges tend to get dry powder, while areas closer to the coast or lower elevation often see wetter, heavier snow that clings longer. This pairs with your cold climate efficiency numbers to round out the full winter picture.

Step 3

Consider your post-storm sun pattern

Many mountain locations see quick clearing after storms, which can melt snow off panels faster than the snowfall total alone would suggest. After a mountain storm the sun comes back in patches, and the winter storm backup planning calculator sizes the backup for the gaps.

Step 4

Set your tilt and removal plan

Combine tilt, mounting height, and removal habits for a final number. Steep mountain roofs already shed snow well without much intervention.

Understanding snow loss in the Mountain West

Why mountain conditions cut both ways

A high-elevation Mountain West system with 90 inches of annual snowfall, dry powder snow, and frequent post-storm clear skies loses around 3% of annual output. An 11,000 kWh/year system loses roughly 339 kWh a year under those conditions. That number stays surprisingly moderate despite heavy total snowfall, because two regional traits work in the homeowner's favor. A DOE federal PV performance study notes that snow cover is treated as a measurable rather than predictable loss, so it is not baked into standard output models.

Dry powder clears faster than wet snow

Dry powder has less moisture to bond it to the glass surface, so it slides off with gravity alone once panels warm slightly. Wet, heavy snow sticks and compacts, which is why coastal mountain areas with wetter storms see longer snow-cover periods than dry inland ranges at similar elevation.

Strong sun clears snow quickly after storms

Many Mountain West locations see clear skies return within a day or two after a storm, and intense high-altitude sun combined with dark panel glass can clear snow faster than at lower, cloudier elevations even with similar total snowfall. This is a big reason mountain snow loss estimates often come in lower than total snowfall alone would predict. National Solar Radiation Database show the Mountain West as one of the sunnier regions nationally even accounting for winter storm activity, consistent with the fast post-storm clearing described here.

Elevation raises snowfall but doesn't always raise loss

Not automatically. Higher elevation often brings more total snowfall and colder temperatures that slow melting, but it also tends to bring stronger, more direct sun exposure and drier powder snow that clears faster. The two effects partly offset each other. Check the cold climate efficiency gain calculator to see how altitude and temperature affect panel output separately from snow cover. If this is for a mountain cabin used mainly in winter rather than a year-round home, the cabin winter-only use sizing tool is built around exactly that seasonal usage pattern.

What to do with this number next

Compare your result against the Northeast or Midwest tools if you're weighing locations, or run the output vs usage gap analyzer to see how winter output lines up with your household's needs.

Questions

Frequently asked

A high-elevation Mountain West system with 90 inches of annual snowfall, dry powder snow, and frequent post-storm clear skies loses around 3% of annual output. An 11,000 kWh/year system loses roughly 339 kWh a year under those conditions.

Dry powder has less moisture to bond it to the glass surface, so it slides off with gravity alone once panels warm slightly. Wet, heavy snow sticks and compacts, which is why coastal mountain areas with wetter storms see longer snow-cover periods than dry inland ranges at similar elevation.

Yes. Many Mountain West locations see clear skies return within a day or two after a storm, and intense high-altitude sun combined with dark panel glass can clear snow faster than at lower, cloudier elevations even with similar total snowfall.

Not automatically. Higher elevation often brings more total snowfall and colder temperatures that slow melting, but it also tends to bring stronger, more direct sun exposure and drier powder snow that clears faster. The two effects partly offset each other.

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