Himalaya Atlas

Next eight hours, town by town

Radar onset is the first extrapolated step with echo of 25 dBZ or more within about 7 km. Model rain is the sum of the forecast's hourly rain from now to +8 h. Select a town to zoom to it.

What happens when

Ground truth: airport reports

METARs from aviationweather.gov: the latest report in the last 3 hours from each airport within about 60 km of mountains over 1,500 m. Hover a station on the map for the raw report. IMD and Nepal DHM automatic stations publish only through their websites and aren't included.

Earthquakes

USGS earthquake catalogue (earthquake.usgs.gov), magnitude 3 and above in the last 30 days within the map's bounding box. India's own National Center for Seismology (seismo.gov.in) has no public API for this, only its own portal and app, so the global USGS feed is used instead. Circle size scales with magnitude; colour fades from recent (orange) to older (tan). Hover a marker for magnitude, depth and time.

Satellite imagery and flood extent

True colour is a daily MODIS Terra photo (NASA GIBS), for real cloud, snow and haze context that neither the radar nor a precipitation layer can show. Flood extent is MODIS's near-real-time Global Flood Mapping product: observed surface water and flood, not the modelled river discharge shown elsewhere. Most of that product's frame is masked "insufficient data" and is hidden; only surface water, recurring flood and active flood pixels are drawn.

Air quality

Three Sentinel-5P TROPOMI products (a joint ESA/NASA instrument), fetched from NASA GES DISC with the most recent one or two orbit segments that crossed the map. Coverage is whatever the satellite happened to see on its last daytime pass, so gaps and stripes are normal, not a bug. Low-quality retrievals (qa_value below 0.5) are dropped before drawing. NO2 (pale yellow to deep red): traffic and industrial nitrogen dioxide. CO (pale tan to near-black): carbon monoxide from combustion and biomass-burning smoke - worth watching every autumn when Indo-Gangetic crop-stubble burning drifts into the foothills. Dust & smoke index (UV Aerosol Index, lilac to deep purple): absorbing aerosols from dust storms or smoke plumes, visible even through thin cloud where the gas retrievals fail.

Rivers: flow against normal

Modelled discharge from GloFAS v4 (via the Open-Meteo Flood API), not a measured river stage. Grey band: 10th–90th percentile of the same calendar days over the last 15 years; line: last 60 days and 7-day forecast. Lake levels have no free live source, so lakes show extent only.