Braided

Safety and data

Safety and data · updated 12 November 2026

Braided is a good way to decide where to look. It is not a way to decide that a place is safe.

What this is

Braided takes no measurements of its own. Everything here was collected by someone else and published for anyone to use: councils, LAWA, DOC, GeoNet, LINZ, Fire and Emergency, MPI, MetService's public warnings feed, NOAA and open global models. We gather it on a schedule, rank it against each site's own record, and put it on a map.

We do not check whether a reading is right: a gauge can be blocked, drifting, frozen, or repeating the last value it managed before it went quiet, and none of that is visible to us. The agencies whose data this is have not reviewed this app, do not endorse it, and are not responsible for anything it says.

A gauge measures one point

A river gauge measures the water at the gauge, not the ford three kilometres upstream, the side creek below it, or the crossing on the tributary. Those can be higher, faster and colder, and can change in minutes. Rain in the headwaters reaches you before it reaches the gauge, and the gauge before your phone: a falling river on this map can be a rising river in front of you.

Most gauges measure height, not flow. Where a card shows cubic metres a second, the council derived it from the height using a rating curve fitted to hand-taken measurements. The curve moves when the bed does, and above the highest flow ever measured there it is extrapolation, so the flow is least certain exactly when it matters most. Some gauges are never rated and show only a height.

Look at the water. If you are in doubt about a crossing, stay out of it.

Every reading here has already travelled

From the gauge to the council, to us, to your phone, and on a downloaded region from your phone's own storage. The time under each number is when it was measured, never when you are reading it, and where that gap is large the app says so and drains the colour out of the reading.

Coverage is uneven. Several councils publish nothing we can use, so some of the country's largest rivers have no gauge here at all. An empty stretch of map means we have no data, not that there is nothing to worry about.

Predictions are not measurements

Tides are LINZ predictions for a standard port, above chart datum. Wind and pressure move both the height and the time, and a storm surge moves them a lot. Not for navigation: a vessel needs the official tables and charts.

LINZ predicts 15 ports in full and publishes most of the coast as an offset from one of them. Where Braided shows one of those places, the times and heights are worked out from the offset, not predicted, and the card says so and prints how wide LINZ's own published range is for that port: typically half an hour on the time and about 0.2 m on the height. A port whose range is wider than 45 minutes is left out rather than shown with a caveat.

The forecast on a card is an open global weather model, not a New Zealand forecaster looking at New Zealand terrain. In the mountains it will be wrong more often than MetService is. Treat it as the shape of the weather, not the weather.

Two numbers on that forecast are easy to read as something they are not. A rain chance is the model's probability that an hour is wet, not how much falls in it. A 70% chance of a tenth of a millimetre and a 20% chance of ten millimetres are both ordinary, so the card prints both figures and never merges them. And the freezing level is the height of the 0 °C line above sea level, not a snow line: snow generally settles some hundreds of metres below it, by an amount that depends on how hard it is falling, and Braided does not work that out for you.

Where Braided carries somebody else's hazard product, it repeats their words and links to them, and theirs is the version that counts: the fire season from Fire and Emergency, severe weather warnings from MetService's own feed, fishing and shellfish restrictions from MPI. Avalanche, tsunami and civil defence it does not carry at all, only links. Follow the link before you rely on it.

BRAIDED DOES NOT CARRY SHELLFISH BIOTOXIN WARNINGS. Those are the warnings that close a beach to gathering at short notice because the shellfish there can make you seriously ill, and MPI publish them on their own site and nowhere Braided can read. The restriction rows on a coastal card come from MPI's fishing regulations, which are a different thing: they say where the rules are, never that the shellfish are safe to eat. A card with no restriction on it is not permission either: MPI's areas cover a fraction of the coast. Check MPI before you gather, every time.

A track's line, grade, times and alerts are DOC's. Its elevation profile and climb are Braided's, read off the LINZ elevation model at about 28 m, so they show where the climbing is and roughly how much, not every bluff. A track with no alert is a track DOC has published nothing about, not one DOC has checked today. Where a track card lists a river, that is where DOC's line meets a river we hold a gauge for: the reading is from that gauge, which can be kilometres from the crossing, and Braided does not know whether there is a bridge.

Braided shows no avalanche danger. In the mountains a card links to the NZ Avalanche Advisory, and a card with no link is not a statement that there is no avalanche risk. Read the advisory before you commit to any terrain.

Alerts are a convenience, not a safety line

A river alert fires when a reading we have received crosses a threshold. It can be late and it can never arrive: the gauge reports on its own schedule, our collection runs on ours, and delivery depends on Apple, Google, the network and your phone being on and in coverage. None of that is under our control.

No alert has ever meant a river is safe to cross. It means a number moved.

Who to ask instead

In an emergency, call 111.

Tell someone where you are going and when you expect to be back. Carry a distress beacon in the backcountry.

The legal part, briefly

Braided is free, non-commercial and provided as it is, with no warranty of any kind. We do not promise that the data is accurate, complete, current or available, that the app will work, or that a notification will arrive.

What you do with what you read here is your decision. To the fullest extent the law allows, neither Braided nor the agencies whose data it shows accept liability for any loss or damage arising from use of the app or anything in it. Nothing in this affects your rights under New Zealand consumer law, or limits any liability that cannot lawfully be limited.

New Zealand law applies. Braided is built and run by one person in Aotearoa New Zealand.