WayCast finds the places on your route where water collects, and tells you how much rain it takes to put them under. It does this by reading the shape of the road — the dips, and whether the ground beside them is high enough to trap water — and combining that with the rainfall forecast and the drains and culverts mapped along the way.
No commercial navigation app does this. What strands a driver in an Indian monsoon is rarely a river in flood; it is one underpass or one low junction that goes under after 60 mm in two hours. That is the question WayCast was built to answer.
The weather it shows is live satellite, not a forecast. WayCast reads Meteosat-9, parked over the Indian Ocean at 45.5°E, which images the whole subcontinent every 15 minutes — the rain rate sensed from infrared and microwave together, storm tops, cloud height and air-mass instability. A forecast says what should happen; this shows what is happening. Each image carries the time it was taken, on screen, so you always know how old the picture is rather than assuming it is current. The service runs roughly half an hour behind real time, which is the normal delay for getting an image down from orbit and processed.
It also keeps the weather with the journey. Navigation apps show you a route; weather apps show you a forecast; neither records what the two did together. WayCast writes a travelog for every drive — the road's rise and fall, the rain that fell on it, the temperature and pressure at the time, and the low points you passed — so a journey can be read afterwards against the conditions that produced it. That is what makes a flooded junction explainable rather than merely remembered, and it is why the same drive is worth recording twice.
The results are modelled, not measured. Nobody has been to your road to look. The app calculates what ought to happen from the terrain and the forecast, which is useful, and is not the same as knowing. Use it as a second opinion alongside your own judgement and what the authorities say.
What goes into it, and how good each part is:
And the world moves. A culvert blocks with debris. A pump loses power in the storm that needed it. A new wall changes where water goes. Roadworks lift a carriageway. None of that reaches the model, and any of it can turn a safe prediction into a wrong one within an hour.
Every model is an approximation — including this one. That is not a defect peculiar to WayCast; it is what a model is. A weather forecast, a flood forecast and a bridge design are all approximations, and all of them are useful because their errors are known and bounded. The work now is to establish those bounds for this one.
That is what this season is for, and why your reports matter. Each time you confirm that a junction flooded as predicted, or tell us it stayed dry, that site gets calibrated — and the trigger for it becomes a measured figure rather than a computed one. Confirmations are as valuable as corrections. A model tested against enough real drives stops being a guess and becomes evidence, and that is precisely what we intend to demonstrate.
What it is not. WayCast does not replace the India Meteorological Department, the Central Water Commission, or the police and authorities on the ground. If any of them says do not travel, or do not use that road, they are right and this app is not. Never enter flowing water because a screen said the depth was survivable — 15 cm of moving water floats a small car.
Apache Licence 2.0 · provided without warranty of any kind · Dr. Dhananjay A. Sant, National Institute of Advanced Studies, Bengaluru