GridWatch | Power Grid Stress During Extreme Weather

How to read this map

Hazard / signal: Extreme weather
Exposure: Grid geography and population
Consequence / vulnerability: Derived grid-weather stress

Official/source values remain distinct from MitchellCo derived screening scores or estimates. Derived values are for prioritization and interpretation, not official warnings or predictions.

Where could extreme weather coincide with thin historical grid margins and high human exposure?

Combines live NWS weather alerts with balancing-area capacity/load baselines, population and social vulnerability. Screening only: this is not a real-time grid-operations dashboard or outage prediction.

Data health

NWS extreme-weather alertsLoading

Grid control areasLoading

CDC county exposureLoading

Transmission linesOff

Oldest consequential input: waiting…

Layers Derived weather-grid stress NWS extreme-weather alerts Control-area boundaries Archived transmission lines

Highest derived grid-weather stress

#	Control area	Weather	Score
Waiting for regional layers…

How the score works

Weather hazard, max 40
max active NWS extreme-weather product intersecting the control area, weighted by event type/severity.

Historical operating margin, max 35
margin = (available capacity − peak load) / peak load. Lower or negative legacy margin scores higher.

Population exposure, max 15
min(15, 2.5 × log10(population assigned by county interior points)).

Social vulnerability, max 10
10 × population-weighted mean CDC SVI rank.

Total = sum, capped at 100. This is a non-official screening index. Historical capacity/load values are not current operating conditions.

Time-series view

Click a ranked control area or shaded polygon to load an on-demand 48-hour Open-Meteo temperature/apparent-temperature forecast at that area's representative point. The sparkline is weather context only and is not silently converted into actual electricity demand.

Loading & reliability

Heavy ArcGIS polygon layers load as four bounded chunks with at most three requests in flight. Independent sources load in parallel, stale requests are aborted on region changes, and scoring yields to the browser every few control areas. API timeouts are 25 seconds with retry/backoff. Scheduled NWS refresh pauses while the page is hidden or offline. Optional transmission geometry loads only when enabled.

Sources, vintages & omissions

National Weather Service Alerts API: active extreme heat/cold, severe storm, high-wind, ice and winter-weather products; refresh every 5 minutes; zone-based alerts are resolved to official NWS zone geometry.

Electric Control Areas / Balancing Areas: static GIS layer with legacy available-capacity, peak-load and total-capacity fields; source layer last edited 2021. Loaded once per region.

CDC/ATSDR SVI 2022: county population and overall SVI rank; static 2022 vintage.

Archived U.S. electric transmission lines: HIFLD-derived 2023/2024-era public copy, no longer updated; optional context only.

Open-Meteo Forecast API: keyless, CORS-enabled 48-hour hourly forecast requested on demand at the selected control-area point; cache 30 minutes; attribution CC BY 4.0.

Omitted: live EIA balancing-authority demand/generation. EIA's API requires a registered API key, which violates this map series' no-key rule. Therefore this map must not be interpreted as live reserve margin, generation adequacy, or outage risk.

© 2026 MitchellCo · Product blog Inc.
Map tiles © OpenStreetMap contributors. NWS/NOAA, CDC/ATSDR, control-area and transmission source data retain their own attribution and terms. Open-Meteo data: CC BY 4.0.