Today’s warning doesn’t mention Matara Four Gravets

We don’t know about closures or damage: call 119 before you set off.

NBRI, issued Fri 9 Oct, 16:00 · valid to Sat 10 Oct, 16:00lankawatch.org

Rain hereAbout 3 days a month are this wet hereLast 24 hours · Satellite estimate Nearest rain gaugeThalgahagoda ≥ 4.3 mmLight rain or more · 6 km away Met advisoryAdvisory for Severe LightningAmber, as issued RiversThalgahagoda: Below Alertsteady

Next update usually tomorrow by 17:45.

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Roads from Matara Four Gravets How we know

Rain here

Last 24 hours: Unusual here (3 days a month) · Amber · Advisory for Severe Lightning

Last 24 hours: among the wettest 10% of 24-hour periods since 2000 in Matara Four Gravets.
Compared with each division's own satellite record since 2000. This is not a warning and does not replace NBRI's levels. Satellites can miss heavy local downpours, so it never means a road is safe. Satellite data up to 9 Oct, 15:30.

Weather forecast (Department of Meteorology) · Amber · Advisory for Severe Lightning

Amber · Advisory for Severe Lightning. For Western, Sabaragamuwa, Central, Uva, North-western, Southern provinces and Anuradhapura, Mannar districts.. Thundershowers accompanied with severe lightning are likely to occur at several places in Western, Sabaragamuwa, Central, Uva, North-western and Southern provinces and Anuradhapura and Mannar districts. There may be temporary localized strong winds during thundershowers. General public is kindly requested to take adequate precautions to minimize damages caused by lightning activity. Issued 9 Oct, 11:00 · Valid until 10 Oct, 01:00.
Forecast issued 9 Oct, 14:00
Showers or thundershowers will occur in the most part of the island after 1.00 p.m.
Covers Matara on this road: Fairly heavy falls above 75 mm are likely at some places in Western, Sabaragamuwa, Central, Uva, North-Western and Southern provinces.
The general public is kindly requested to take adequate precautions to minimize damage caused by temporary localized strong winds and lightning during thundershowers.
Misty conditions can be expected at some places in Western, Sabaragamuwa, Central and Uva provinces during the early hours of the morning.
A forecast never lowers or replaces the NBRI landslide warning above.
Forecast and advisories by the Department of Meteorology, Sri Lanka, as issued. LankaWatch is not an official service.

Rain outlook (computer model) · Next day: Not signalled

Next day: unusually heavy rain is not signalled for the divisions on this road. (10 Oct, 05:30 to 11 Oct, 05:30)
Next 3 days: unusually heavy rain is not signalled for the divisions on this road. (10 Oct, 05:30 to 13 Oct, 05:30)
"Not signalled" never means dry or safe. This is a computer model, not a warning, and it never changes NBRI's levels. Like the satellite, it reads hill-country rain low and can miss heavy local downpours.
ECMWF ensemble forecast (open data, CC BY 4.0), run 9 Oct, 05:30, compared with each division's own satellite record.

None of these changes NBRI’s level.

Weather forecast (Met Dept)

Amber · Advisory for Severe Lightning. For Western, Sabaragamuwa, Central, Uva, North-western, Southern provinces and Anuradhapura, Mannar districts.. Thundershowers accompanied with severe lightning are likely to occur at several places in Western, Sabaragamuwa, Central, Uva, North-western and Southern provinces and Anuradhapura and Mannar districts. There may be temporary localized strong winds during thundershowers. General public is kindly requested to take adequate precautions to minimize damages caused by lightning activity. Issued 9 Oct, 11:00 · Valid until 10 Oct, 01:00.
Forecast issued 9 Oct, 14:00
Showers or thundershowers will occur in the most part of the island after 1.00 p.m.
Covers Matara on this road: Fairly heavy falls above 75 mm are likely at some places in Western, Sabaragamuwa, Central, Uva, North-Western and Southern provinces.
The general public is kindly requested to take adequate precautions to minimize damage caused by temporary localized strong winds and lightning during thundershowers.
Misty conditions can be expected at some places in Western, Sabaragamuwa, Central and Uva provinces during the early hours of the morning.
A forecast never lowers or replaces the NBRI landslide warning above.
Forecast and advisories by the Department of Meteorology, Sri Lanka, as issued. LankaWatch is not an official service.

Rivers and catchments here

2 named rivers here · 1 basin

River basins this division lies in

Nilwala Ganga basin

Satellite rain over these basins

Nilwala Ganga basin · Last 3 days: Unusual here (3 days a month)

A whole-basin satellite average against that basin’s own record since 2000, not the area upstream of any one point. Satellites under-read hill rain. Not a warning.

Named rivers through this division

Nilwala Ganga · about 6 km inside
Galtota Ela (Nilwala Ganga basin) · about 2 km inside

Irrigation Department gauges on these rivers

Thalgahagoda, an Irrigation Department gauge 6.5 km upstream (655 km² upstream · rain over that area, Last 3 days: Unusual here (3 days a month)): at least 4.3 mm in the 24 hours to 9 Oct, 08:30 (2 hourly readings missing); 0.9 mm in the 3 hours to 9 Oct, 20:04.
River level 0.93 m · Below Alert · steady over about 3 hours (Department’s thresholds: Alert 1.4, minor flood 1.7, major flood 2.8 m)

Rivers and basins come from our own map of Sri Lanka’s river network. Flow direction, where shown, is worked out from the height of the land. This is orientation only, not a flood warning.

The area draining to a crossing is worked out from a terrain model (about 90 m cells) and is approximate. The rain over it is the satellite average for that same area, against its own record since 2000. Areas under about 150 km² are smaller than the satellite can see, so they show no rain.

River levels are the Irrigation Department’s own readings at its gauge, against its own thresholds. This is not a flood warning: flood warnings come from the Irrigation Department and DMC.