Measurement
Snow-aligned production residual
- ID
meas:snow-production-residual- IRI
https://solarlattice.org/kb/meas/snow-production-residual- Status
- active
- Also known as
- Snow cover loss, winter residuals, SCADA production residuals
This signature is a shortfall between measured production and expected snow-free production that lines up in time with snowfall and snow on the modules. The plant can be available, and irradiance sensors can show usable resource, while snow-covered modules still produce little or no current. The loss often appears suddenly after snowfall, then fades gradually as the snow melts or slides off. Partial clearing can leave string and substring currents uneven, so the residual does not always scale with how much snow you can see. To confirm it, line up the SCADA residuals with timestamped snowfall, snow depth, temperature, wind and plane-of-array irradiance, plus camera, drone or field observations; a heated POA pyranometer helps provide the irradiance reference. Not every winter residual is snow: filter out cold-weather inverter behavior, clipping, curtailment, trackers frozen in stow, iced sensors and albedo effects before estimating the loss. If measured recovery after snow is slower than the energy model assumes, the model's snow-loss factor may need revising even when the equipment is working normally.
Signals
Monitoring channels where this signature appears, named by SunSpec model point.
| Point | Unit | Pattern |
|---|
model_103.W | W | abrupt drop after snowfall, gradual recovery during melt |
model_302.POAI | W-PER-M2 | usable irradiance reported while output stays low |
model_303.TmpBOM | DEG_C | module temperature used alongside residuals to follow melt |
model_307.TmpAmb | DEG_C | cold conditions that slow snow clearing |
Claims
typical_power_loss
c1 verified · fact
≤ 10 PERCENT
Conditions: Yearly snow losses for standard framed modules at latitudes above 60°N in Sweden; 'most often' less than this
verified by: joshuahamsaverified on: 2026-10-20review note: support check: partial - Passage says losses are 'most often less than 10%' yearly; the statement frames this as 'up to 10%' typical, which is roughly equivalent but an upper bound rather than typical.; possible conflict with c2 (same source; check the conditions); possible conflict with c3 (same source; check the conditions); possible conflict with c4 (same source; check the conditions); possible conflict with c7 (same source; check the conditions)
c2 verified · fact
nominal 18 PERCENT
Conditions: Annual production loss, snow-covered vs cleaned modules side by side, Sierra Mountains USA, 0° tilt (Powers et al.)
verified by: joshuahamsaverified on: 2026-10-20review note: possible conflict with c1 (same source; check the conditions); possible conflict with c3 (same source; check the conditions); possible conflict with c4 (same source; check the conditions); possible conflict with c5 (same source; check the conditions); possible conflict with c7 (same source; check the conditions)
c3 verified · fact
nominal 15 PERCENT
Conditions: Annual production loss, snow-covered vs cleaned modules, Sierra Mountains USA, 24° tilt (Powers et al.)
verified by: joshuahamsaverified on: 2026-10-20review note: possible conflict with c1 (same source; check the conditions); possible conflict with c2 (same source; check the conditions); possible conflict with c4 (same source; check the conditions); possible conflict with c5 (same source; check the conditions); possible conflict with c7 (same source; check the conditions)
c4 verified · fact
nominal 12 PERCENT
Conditions: Annual production loss, snow-covered vs cleaned modules, Sierra Mountains USA, 39° tilt (Powers et al.)
verified by: joshuahamsaverified on: 2026-10-20review note: possible conflict with c1 (same source; check the conditions); possible conflict with c2 (same source; check the conditions); possible conflict with c3 (same source; check the conditions); possible conflict with c5 (same source; check the conditions); possible conflict with c7 (same source; check the conditions)
c5 verified · fact
0.3–2.7 PERCENT
Conditions: Annual snow-cover losses, grid-connected frameless modules at 28° tilt, Bavaria, southern Germany
verified by: joshuahamsaverified on: 2026-10-20review note: possible conflict with c2 (same source; check the conditions); possible conflict with c3 (same source; check the conditions); possible conflict with c4 (same source; check the conditions); possible conflict with c7 (same source; check the conditions)
c6 verified · fact
≤ 100 PERCENT
Conditions: Daily loss from snow cover, Konya, Turkey, January 2017, cleaned vs snow-covered modules
Source says daily losses could be almost 100%
verified by: joshuahamsaverified on: 2026-10-20review note: support check: partial - Passage says daily losses could be almost 100% in Konya Jan 2017; 'typical' up to 100% is slightly overstated but the note acknowledges it.
c7 verified · fact
nominal 23 PERCENT
Conditions: Monthly loss from snow cover, Konya, Turkey, January 2017
verified by: joshuahamsaverified on: 2026-10-20review note: possible conflict with c1 (same source; check the conditions); possible conflict with c2 (same source; check the conditions); possible conflict with c3 (same source; check the conditions); possible conflict with c4 (same source; check the conditions); possible conflict with c5 (same source; check the conditions)
Referenced by
Data