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Before you use UpstreamWX — read this.

This tool gathers National Weather Service data, weather-model output, and ensemble probabilities and summarizes them for caving and canyoneering trips. It exists to save you time and to flag hazards worth a closer look.

It does not tell you whether to go. It is not an official forecast or warning. The data can be incomplete, delayed, or wrong — and a slot canyon or cave can flood from rain you never see.

Use it as one input. Check the official NWS sources it links to. In the field, watch the sky and the water: what you observe there beats anything on this screen. The decision to enter, continue, or turn around always rests with you and your party.

Plan expedition

Long-press the map to drop a point, or drag the marker to reposition. Search © OpenStreetMap contributors.

Radius of Concern 20 mi
102050100200

Caps the upstream watershed — the basin is clipped to this radius before weather data is gathered.

Add to Home Screen

Safari's address bar with the three-dot More button circled at its right
Step 1 Tap ••• to the right of the address bar.
The Safari menu with the Share row highlighted at the top
Step 2 Tap Share at the top of the menu.
The share sheet scrolled to the highlighted Add to Home Screen row
Step 3 Scroll down, tap Add to Home Screen, then tap Add.

Settings

Units

Temperatures, wind, precipitation, and distances are shown in your chosen system throughout the app.

Lightning Area of Concern (LAoC) 15 mi
10152550100

Lightning risk is assessed within this radius of the activity, rather than across the whole upstream watershed.

Default approach time 1 hr
30m1 hr1½ hr2 hr3 hr

Time before the in-cave/canyon window used for approach-phase hazard weighting.

Default egress time 1 hr
30m1 hr1½ hr2 hr3 hr

Time after the in-cave/canyon window used for egress-phase hazard weighting.