Is Giriulla flooding now?

As of Tue, 27 Oct, 12:04 am (Sri Lanka time), the Maha Oya at Giriulla was 16.9 ft, close to the 18.0 ft alert level, and rising slowly.

Will the Maha Oya at Giriulla rise in the next hour?

In the next hour the Maha Oya at Giriulla could rise to about 17.0 ft (16.8–17.1 ft). This is a forecast from the recent trend, the gauges upstream and rain, not an official warning.

What is the flood level at Giriulla?

The official marks for this gauge are alert 18.0 ft, minor flood 21.3 ft, major flood 24.6 ft. Alert means the river has reached the alert mark: move valuables up and charge your phone. Minor flood means water is spilling over low ground, and major flood means move to safety.

Where does this come from and how often does it update?

River readings come from the Department of Irrigation's gauges, roughly once an hour, and this page checks for new ones every minute. This site is independent and not an official warning service: follow the Disaster Management Centre and call 117 in an emergency.

Giriulla Maha Oya water level today (live)

Reading at 12:04 am · 52 min ago

Normal

16.9 ft

Near alert: 1.2 ft below the alert mark, rising

Next hour

Rising slowly

Next 24 hours

Close to alert level

The level is rising and is forecast to reach about 17.0 ft in an hour.

Details

Rising: about 17.0 ft in an hour.

Published as 5.14 m (alert 5.5 m, minor flood 6.5 m, major flood 7.5 m)

In	Level	80% range	At
1h	17.0 ft	16.8 to 17.1	1:04 am

Local trend

+0.1 ft/h

Upstream avg

n/a (top)

Rain that fell: 1.2 mm in the last 3 hours, 77 mm in the last 24 hours at this gauge (heavy rain) (heavy for this river)
Rain forecast: 7.2 mm in the next 24 hours over the catchment (light rain). Forecast model estimate.

Satellite estimate of rain over the catchment: 7.6 mm in the last 6 hours, 109.4 mm in the last 24 hours (to 12:30 am). It can differ from the gauges. GSMaP data by Japan Aerospace Exploration Agency (JAXA)

· Trend only: a rain model was fitted and tested on 8 days but was no more accurate than "level stays put" at any horizon (best: 1 h, 0.043 vs 0.045 error).
· Forecast model estimate of catchment rain (Open-Meteo, area average over 20 grid cells above this gauge): 10.1 mm modelled for the last 6 hours, 75 mm modelled for the last 24 hours, 7 mm forecast for the next 24 hours. The model's past hours often read lower than the gauges, so they are not what fell; this note is for context.
· Topmost gauge on its river: no gauge upstream, so only its own trend (plus catchment rain) is available.

How this is worked out
· This gauge's own recent changes and the other gauges on the river, fitted to about 11 months of hourly readings (one hour ahead only). In a backtest on the last 60 days it missed by less than 'no change'. This is the topmost gauge on its river, so there is no upstream gauge; the catchment rain above is the only upstream signal.

Is this right?

Each answer helps us improve the forecast for your area.

Water level

How this river reacts to rain

A slow river. Rain close to Giriulla shows up in the river in about 20 hours.
About 30 mm of rain over 24 hours, averaged over the catchment, has usually come before a rise of 1 ft or more.

Learned from 11 months of readings and satellite rain. A guide, not a forecast.

This gauge’s forecasts: the next hour is typically off by about 0.2 ft (last 30 days, 29 checks).

When does Giriulla flood?

Flood warnings come mostly in November.

It’s October: floods are less common than in November, but they do happen.

Recent floods

27 Nov – 30 Nov 2025Major flood
21 Oct – 26 Oct 2025Major flood · estimated
26 Nov – 2 Dec 2024Major flood · estimated

Every day since 2022, year by year

Other stations

Along the Maha Oya

Arrows show the change over the last 3 hours.

Towns that depend on this gauge

Flood help & emergency numbers

Common questions

Is Giriulla flooding now?: As of Tue, 27 Oct, 12:04 am (Sri Lanka time), the Maha Oya at Giriulla was 16.9 ft, close to the 18.0 ft alert level, and rising slowly.
Will the Maha Oya at Giriulla rise in the next hour?: In the next hour the Maha Oya at Giriulla could rise to about 17.0 ft (16.8–17.1 ft). This is a forecast from the recent trend, the gauges upstream and rain, not an official warning.
What is the flood level at Giriulla?: The official marks for this gauge are alert 18.0 ft, minor flood 21.3 ft, major flood 24.6 ft. Alert means the river has reached the alert mark: move valuables up and charge your phone. Minor flood means water is spilling over low ground, and major flood means move to safety.
Where does this come from and how often does it update?: River readings come from the Department of Irrigation's gauges, roughly once an hour, and this page checks for new ones every minute. This site is independent and not an official warning service: follow the Disaster Management Centre and call 117 in an emergency.