Storm Dennis

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Storm Dennis 15 Feb – 16 Feb 2020 2019-20 season Wales, England Cat 5 · Extreme Full storm page →
128 mph max gust 158 mm peak rainfall 825 flood warnings & alerts, 8 severe England 761 warning areas 406 rivers 5 UK deaths
Worst-hit areas (warnings)
River Severn at East Waterside, Upton upon Severn4
Barcombe Mills3
Eastern Yar3
Lower Arun3
Climping Seafront2
Worst-hit districts (warnings)
Worcestershire60
Staffordshire55
Derbyshire52
Hampshire51
North Yorkshire50
Worst-hit rivers (warnings)
River Severn35
River Trent21
Groundwater18
River Wye18
River Teme17
🌀 the whole storm
Rivers <50%50–7575–9090–100record Rain light ⟶ torrential ▲ rising warningsevere 🏠 you
⏩ Worst moment, aftermath, similar storms, the storm's fingerprint
🔎 checking what live river conditions resemble…
🏠 Your postcode in this storm: nearest gauges, the local fingerprint, similar moments
Type your postcode in the box above the map.
🌊 Every river in this replay, and add one
⚠️ Official warnings day by day, the severe ones, and the records broken
🗺 Map layers, the weather model, and how to read this replay
— isobarsLH
🌦 weather: waiting for a replay…
  • The map shows the weather that caused the flood under the rivers it flooded, on one clock. Each circle is a river gauge: it grows and turns red as that river climbs toward the highest level ever measured there. ▲ beside it is how fast it is rising, in cm per hour. Each rain gauge glows with the rain of the last hour, on the same colour scale as the model's rain band under the map. The band and the isobars are ERA5, a reanalysis: a model run with the observations of the time, not measurements.
  • The small map in the corner is the whole weather system, so you can see where the low is while the main map stays on your area. Click it to zoom out, click again to come back.
  • The timeline under the map is your doorstep: rain every 15 minutes at the nearest rain gauge, the nearest river as a share of its record, warnings as flags. The future is ghosted until the clock reaches it, so at every moment you see only what a person there could have known. Click or drag on it to move the clock.
  • The panel on the right is right now, at your door: the last hour's rain, the river's level and rise, the warnings out, the pressure. Below it, the story: the moments that mattered, ticked off as the clock passes them. Click one to jump to it.
  • Speed is replay time per real second. At 1 hour per second a day takes 24 seconds. ← → step 15 minutes (with shift, an hour); space plays and pauses.
  • Enter your postcode in the box above the map and the map, the timeline and the story centre on your address, pulling in the river and rain gauges nearest to you. Warnings are England only (Environment Agency data).