How much rain the weather model puts on the slopes along QL4D — where the landslides that cut Sa Pa off come from — and what it expects next. Not a road report.
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When Sa Pa is cut off, it is almost always the rain on the slopes above the road, not the rain falling on the town. The single corridor in and out — QL4D over the Ô Quý Hồ pass to the west, and the connector dropping past the Móng Sến toll to the Nội Bài–Lào Cai expressway to the east — is buried by landslides again and again in the rainy season (April–October). This page reads a weather model's rainfall at points along that corridor, from the high pass down to the descent, so you can see how much has fallen on the slopes and what the model expects next. It is not a road report and not a landslide warning.
The real warnings come by radio
The rainy season is when the road slides
Heavy rain has fallen over the Móng Sến descent in the last two days — about fifty millimetres.
Over the next two days the model expects heavy rain over the Móng Sến descent — about forty millimetres.
These are weather-model estimates of rain, not measurements — and rain figures are never a flood forecast.
From the high slopes down to town — the order the water travels. Rain up top can reach the valley hours later; rain in town says little about what is coming downstream.
Where QL4D crosses the Hoàng Liên Sơn ridge west of town, by Thác Bạc (Silver Falls) and the head of the Mường Hoa valley. Rain on these steep, bare slopes runs off fast — onto the road and down toward town.
The town in its high valley, where the Suối Mường Hoa gathers the water off the slopes. The streets and terraces below the slopes take the runoff first.
The connector dropping from town to the Nội Bài–Lào Cai expressway, past the Móng Sến toll — the stretch buried by the landslide on 1 July 2025 and cut repeatedly since Typhoon Yagi.
Every figure here is a weather model’s estimate for an area, not a rain gauge and not a river gauge. The model works on a coarse grid — one mountain valley can catch a storm the model spreads across the whole slope, or misses.
“Heavy rains since Saturday night had triggered serious landslides along some roads leading from downtown Sa Pa to the area.”
That experience is the honest frame for this page. Heavy rain on the mountains is a reason to be more watchful; calm skies are never a promise of safety. This page can add context — it can never replace the warning chain above.
Plain sentences a presenter can read on air, checked 27 June at 8:31.
Rainfall update for the mountain catchments above town — the Suối Mường Hoa and the the slopes along QL4D over the Ô Quý Hồ pass and the Móng Sến descent — from the Open-Meteo weather model.
In the last two days the model estimates about thirty-five millimetres of rain over the Ô Quý Hồ pass and the high slopes, and about fifty millimetres over the Móng Sến descent.
Over the next two days it expects about twenty-five millimetres over the Ô Quý Hồ pass and the high slopes.
These figures come from a weather model — they are estimates, not measurements, and they are not a flood warning.
For whether the road is actually open, check Báo Lào Cai and the road operator and the official forecast at nchmf.gov.vn — not this page.
Updated 27 June at 8:31. Rainfall figures are model estimates from Open-Meteo (CC BY 4.0), read at the points named above; high-slope points use an elevation setting so the model downscales to that height. No river-level gauge feeds this page — none is publicly available here.