Official alerts

What they are

An official alert is what a national weather service has issued: a Winter Storm Warning, a Wind Advisory, a Tornado Watch. Windshield Weather shows the alerts the US National Weather Service has in force, and the wildfires burning in the United States, on the map and on your drive, and names who issued each one. On a drive into Canada it also shows the alerts Environment and Climate Change Canada (ECCC) has in force along your route; the map shows US alerts only, for now.

They sit beside the forecast and never change it. Your drive’s ratings, from Calm to Extreme, are our forecast for when you get there; an alert is the weather service’s own statement. A section can be Mild inside a Winter Storm Warning that starts after you have passed, or rated Hazard where no alert is in force. Read both.

How they look

Official alerts are always hatched, with diagonal stripes, and tagged OFFICIAL with the issuer’s name. Our forecast never is.

RED

The most dangerous warnings: tornado, extreme wind, blizzard, ice storm, flash flood, hurricane, fire, and orders to evacuate now.

ORANGE

Other warnings: the hazard is happening or about to.

YELLOW

Advisories, hatched, and watches, outlined only: conditions are favourable for the hazard, nothing more yet.

INFO

Statements, such as a Special Weather Statement or an Air Quality Alert.

A Canadian alert keeps the colour ECCC gives it — yellow, orange or red — and its statements are INFO. Each also carries its word — warning, watch, advisory or statement — so the level never rests on colour alone.

On the map

Turn on weather alerts in the map’s layers to see every alert area in force in the United States. Tap an area to open the alert; where several overlap, you get a list, worst first. Map layers and radar says where the switch is.

Official alerts are reaching accounts gradually. Until yours has them, the weather alerts row in the map’s layers says it is not available yet.

On your drive

When your route passes through an alert while it is in effect, the drive says so: a row such as “2 official alerts on your drive”, each section inside one tagged OFFICIAL, and the route hatched along that stretch. An alert counts when you are inside its area within half an hour of when it starts or ends.

Open an alert to see:

• who issued it, and its name exactly as issued;
• a one-line summary in your language;
• when it is in effect, from when until when, or until further notice;
• when it was issued, and the area it covers;
• the weather service’s full text and instructions, as issued, in English — a Canadian alert too, for now;
• a link to read it where it was issued: weather.gov, or ECCC’s api.weather.gc.ca for a Canadian alert.

Wildfires

Wildfires come from the National Interagency Fire Center, which every US fire agency reports into, CAL FIRE included. Each fire is drawn as its mapped perimeter, or, until one is mapped, as a circle of its reported size, with a flame where it started — larger for a larger fire. Zoom in to read its name, size and containment, and tap the flame to open it.

Fire agencies give a fire no warning level, so Windshield Weather gives it one:

ORANGE

A fire under 90% contained that has a mapped perimeter or has reached 10 acres.

YELLOW

A fire 90% contained or more, or one under 10 acres reported in the last three days.

Fully contained fires, prescribed burns and small fires with no news for three days are left off.

On your drive, a fire counts when your route passes within 5 km (3 miles) of it, not only through it, and its row says how close: “1.2 mi from your route”, or “Across your route”. Open it for its size, containment, when it was discovered, its cause and the people assigned, as the agency reported them, and a link to its page: CAL FIRE’s incidents for a California fire, InciWeb elsewhere. Drive alerts tell you when a fire is burning near or across your route, and when it is no longer listed. A fire leaving the list does not mean it is out.

The National Weather Service’s own fire alerts are shown like any other: Red Flag Warnings, Fire Weather Watches, Fire Warnings, Extreme Fire Danger statements, and Evacuation Immediate orders.

When alerts are unavailable

Each list is read on its own, and one we could not read is named rather than shown as empty. If we could not read the weather service’s alerts recently, the drive says “Weather alerts unavailable”, with a link to weather.gov, and keeps any fires. If we could not read the fire list for three hours, the drive says “Wildfires unavailable”, with a link to InciWeb, and keeps the weather service’s alerts; the map leaves fires off. If we could read neither, it says “Official alerts unavailable”. On a drive that crosses into Canada each country is read on its own: if one could not be read, the drive names it — “Canadian weather alerts unavailable”, with a link to weather.gc.ca, or “US weather alerts unavailable” — and keeps the other country’s alerts. If we could read nothing on such a drive, each country and the fire list get their own line. An alert past the time the weather service promised to update it is greyed, and then hidden.

Where they come from

The US National Weather Service, part of NOAA: public domain, credited as “Source: NOAA National Weather Service”. Wildfires come from the National Interagency Fire Center’s current incidents and perimeters, credited as “Wildfires: National Interagency Fire Center”. Canadian alerts come from Environment and Climate Change Canada’s public weather alerts, credited as “Data Source: Environment and Climate Change Canada”. Europe and South America are planned.