{"name":"Sommet","version":"0.9","label":"Sommet 0.9","releasedOn":"2026-11-12","tagline":"SnowSure’s own forecast engine, built for the mountain, height by height.","summary":["Sommet is the engine behind every SnowSure forecast. It doesn’t pass on one weather model’s number. It takes up to nine of the world’s weather models as raw ingredients and rebuilds the forecast at the base, mid-mountain and summit of each resort, because rain in the village and snow on top is the whole story of a ski day.","Then it checks its own work. Every night, Sommet’s forecasts are graded against snow and temperature measured at weather stations at the same height, and the grades are public, misses included.","Sommet is learning from those stations too. Corrections taught by thousands of station records run every day in testing, graded against stations they have never seen. Each one goes live region by region, and only when it beats today’s forecast."],"numbersAsOf":"2026-11-12","numbers":[{"value":"500+","label":"ski resorts","detail":"Each forecast at three heights: base, mid-mountain and summit."},{"value":"9","label":"weather models","detail":"Up to nine per resort: seven global, plus sharper regional models where they exist."},{"value":"2,400","label":"weather stations read every day","detail":"Snow, temperature and wind from 26 station networks."},{"value":"439","label":"stations held out for grading","detail":"Never used for training, so every grade is a fair test."}],"engine":[{"id":"models","name":"The world’s weather models as ingredients","status":"live","line":"Seven global models for every resort: ECMWF, NOAA GFS, Canada’s GEM, Germany’s ICON, Japan’s JMA, Météo-France and the UK Met Office. Where sharper regional models exist, they join: HRRR and the National Blend in the US, MeteoSwiss and ItaliaMeteo in the Alps, Met Norway in Scandinavia.","icon":"models","short":"Up to nine weather models per resort, global and regional."},{"id":"heights","name":"Three heights on every mountain","status":"live","line":"Every resort is forecast at its base, mid-mountain and summit, each at its own elevation, with its own temperature, snow and wind.","icon":"heights","short":"Base, mid-mountain and summit, each forecast on its own."},{"id":"snow-ratio","name":"Snow made from water, height by height","status":"live","line":"How much snow a centimetre of water makes depends on the cold: heavy and wet near freezing, light and deep when it’s cold. Sommet sets that ratio from the temperature at each height.","icon":"snowflake","short":"Wet snow near freezing, deep powder in the cold, set at each height."},{"id":"chance","name":"The chance of a big day","status":"pro","line":"The chance of 10, 15 or 25 cm on each day, counted across the 51 runs of the European ensemble, with the likely, low and high totals beside it.","access":"Days 1–7 free; days 8–14 with Pro or on My Mountains.","icon":"chance","short":"The chance of 10, 15 or 25 cm, from 51 ensemble runs."},{"id":"grading","name":"Graded every night, in public","status":"live","line":"Every forecast is scored against measured snow at stations within about 300 m of the forecast’s height, never against another model. The scorecard shows the average miss and how often we called 10 cm and 25 cm days, by region.","href":"/forecast-trust","icon":"grade","short":"Scored every night against snow measured at the same height."}],"products":[{"id":"storm-watch","name":"Storm Watch","status":"live","line":"Storms flagged 3 to 14 days out, with every resort in the path, how many models agree, and the forecast we made before the snow. The archive stays up afterwards, so you can check how we did.","href":"/storm-watch","surfaces":["web","iphone","watch"],"icon":"storm","short":"Storms 3–14 days out, the resorts in their path, and how we did."},{"id":"local-snow","name":"Local Snow","status":"live","line":"A daily forecast discussion for your mountain: the headline, the next 72 hours and days 4 to 7, written every morning and checked number by number against the forecast before it’s published.","surfaces":["web","iphone"],"icon":"discussion","short":"A daily forecast discussion for your mountain."},{"id":"surely","name":"Surely, the snow concierge","status":"live","line":"Ask anything about snow, resorts and trips, and get an answer drawn from SnowSure’s own forecasts and records. Surely can also send you a morning brief.","href":"/concierge","surfaces":["web","iphone","watch"],"access":"Five questions a day free; unlimited with Pro.","icon":"chat","short":"Ask anything about snow, resorts and trips."},{"id":"snow-quality","name":"Snow Quality","status":"live","line":"For every day of snow in the forecast: light, average or heavy, from how much water the new snow holds. In the iPhone app, a beta call on the surface itself, from dry powder to crust, from the snowpack simulation in testing below.","surfaces":["web","iphone"],"icon":"quality","short":"Light, average or heavy: how wet each day’s new snow is."},{"id":"stations","name":"Stations","status":"live","line":"More than 1,100 public weather stations with measured snow depth, country by country: where it’s snowing now, the biggest gains, and every station’s height and source.","href":"/stations","surfaces":["web"],"icon":"station","short":"More than 1,100 public stations measuring snow depth."},{"id":"scorecard","name":"The public forecast scorecard","status":"live","line":"Our published 10-day snow forecasts graded every night against stations held out from training, by region: the average miss, the bias, and how often we caught the 10 cm and 25 cm days. The misses are on it too.","href":"/forecast-trust","surfaces":["web"],"icon":"scorecard","short":"Our published forecasts, graded nightly by region. Misses too."}],"maps":[{"id":"snowfall-map","name":"Interactive snowfall maps","status":"pro","line":"Forecast snowfall across 30 ski regions, from the Alps and the Rockies to Japan, the Andes and New Zealand, for the next 24 hours, 3 days and 7 days, with a day-by-day slider. Updated twice a day in winter.","href":"/maps","surfaces":["web","iphone"],"access":"Up to 7 days free; 14 days with Pro.","icon":"map","short":"Forecast snow across 30 ski regions, day by day."},{"id":"resort-dots","name":"Every resort on the map, five ways","status":"live","line":"Colour the resorts by forecast, SnowSure Score, the last 24 hours, the last 7 days or the season so far. A solid dot was measured; a hollow one is an estimate.","href":"/maps","surfaces":["web","iphone"],"icon":"dots","short":"Every resort coloured by forecast, score or recent snow."},{"id":"radar","name":"Live precipitation radar","status":"live","line":"An animated two-hour radar loop with nowcast frames. It uses national radar in the US, Canada and Japan, with rain and snow in their own colours where the source allows, and a global mosaic elsewhere.","href":"/maps","surfaces":["web","iphone"],"icon":"radar","short":"A live two-hour loop, rain and snow in their own colours."},{"id":"hd-radar","name":"SnowSure HD radar","status":"pro","line":"Our own 250 m radar, built from the raw US weather-radar feed, with a new frame every five minutes across the lower 48.","surfaces":["web","iphone"],"access":"Pro, or free on My Mountains.","icon":"hd","short":"Our own 250 m radar, a new frame every five minutes."},{"id":"forecast-layers","name":"Freezing level, summit wind and temperature","status":"pro","line":"Day-by-day forecast layers for the freezing level, the wind at the summit and the temperature, across each region.","surfaces":["web","iphone"],"access":"Up to 7 days free; 14 days with Pro.","icon":"layers","short":"Freezing level, summit wind and temperature, day by day."},{"id":"mountain-view","name":"Mountain View in 3D","status":"pro","line":"Your resort in 3D terrain, with its runs and lifts, live weather-station pins (gusts, snow depth and the last 24 hours), and webcams placed where they stand.","surfaces":["web","iphone"],"access":"Pro, or free on My Mountains.","icon":"mountain3d","short":"Your resort in 3D: runs, lifts, stations and webcams."},{"id":"slope-layers","name":"Slope angle, avalanche terrain and aspect","status":"pro","line":"Slope steepness, the terrain over 30° where avalanches start, and which way each slope faces, drawn from national elevation surveys around each resort.","surfaces":["web","iphone"],"access":"Pro, or free on My Mountains.","icon":"slope","short":"Steepness, 30°+ avalanche terrain and which way slopes face."},{"id":"station-layer","name":"Snow stations on the map","status":"live","line":"Measured snow depth at public stations, greyed out when a station has stopped reporting.","href":"/maps","surfaces":["web"],"icon":"station","short":"Measured snow depth at public stations, on the map."},{"id":"storm-maps","name":"Storm maps","status":"live","line":"For each storm on Storm Watch: where the snow line sits across the range, and how the snow moves through it.","href":"/storm-watch","surfaces":["web"],"icon":"snowline","short":"Where the snow line sits as a storm crosses the range."},{"id":"snow-level-map","name":"Snow-level map","status":"testing","line":"Where rain turns to snow, every three hours for seven days. It runs four times a day and stays off until its grade picks the method.","icon":"snowline","short":"Where rain turns to snow, every three hours for seven days."}],"learning":[{"id":"overnight-low","name":"Temperature corrections","status":"testing","line":"How each model runs warm or cold at each kind of mountain, learned from two winters of temperature at 900+ stations in North America and Europe, including the time of day each observer reads the thermometer.","graded":"Every night, at held-out stations and every resort height.","reading":{"asOf":"2026-11-11","text":"Overnight lows 10–12% closer to what stations measured than the raw models, and 20–34% closer in the Alps. Not live yet: in the eastern US and Canada it still does worse than the raw models, and a region goes live only when it passes."},"chart":{"asOf":"2026-11-11","measure":"Overnight low, 1–3 days out: how much closer than the raw models","bars":[{"label":"Alps","gainPct":34,"stations":61},{"label":"Cascades","gainPct":12,"stations":32},{"label":"All regions","gainPct":10,"stations":329},{"label":"Rockies","gainPct":9,"stations":154},{"label":"Eastern US & Canada","gainPct":-46,"stations":57}]},"icon":"thermometer","short":"How each model runs warm or cold at each kind of mountain."},{"id":"water","name":"Precipitation corrections","status":"testing","line":"How much water actually falls at each mountain, learned from rain gauges and snow pillows, using how far the models agree as a guide.","graded":"Every night, at held-out gauges and pillows.","icon":"water","short":"How much water really falls, learned from gauges and pillows."},{"id":"phase-ratio","name":"Rain or snow, and how deep","status":"testing","line":"Whether each day falls as rain, a mix or snow, and how deep that snow lands, learned from observers who measure fresh snow on a board every day.","graded":"Every night, against 125 held-out snow boards in the US and Austria.","icon":"phase","short":"Rain, mix or snow, and how deep, learned from snow boards."},{"id":"wet-bulb","name":"Rain or snow by the wet-bulb temperature","status":"testing","line":"Calling rain or snow hour by hour on the wet-bulb temperature, the temperature a falling flake actually feels, at each height. It runs beside today’s rule on every resort.","graded":"Against measured snow, storm by storm.","icon":"phase","short":"Rain or snow called hour by hour on the wet-bulb temperature."},{"id":"snowpack","name":"Snowpack simulation","status":"testing","line":"A physical model of the snowpack at three heights and nine slope directions, behind the next version of Snow Quality. In the iPhone app as a beta.","graded":"Against measured snow depth.","icon":"snowpack","short":"A snowpack model at three heights and nine slope directions."},{"id":"mountain-factor","name":"The mountain factor","status":"testing","line":"The extra snow a mountain wrings out of a storm as air is forced up its slopes, measured for every resort.","graded":"Against measured snow at each height.","icon":"lift","short":"The extra snow a mountain wrings out of a storm."}],"apps":[{"id":"iphone","name":"SnowSure for iPhone","status":"coming","line":"Your mountains at three heights, Storm Watch, Local Snow, Surely, the maps and radar, and alerts for the days that matter.","href":"/app","surfaces":["iphone"],"icon":"phone","short":"Your mountains, Storm Watch, Surely, maps and alerts."},{"id":"watch","name":"SnowSure for Apple Watch","status":"coming","line":"A page for each of My Mountains, the storm brief, the nowcast, roads, and Surely on your wrist, with complications for snow and summit temperature.","href":"/app","surfaces":["watch"],"icon":"watch","short":"Your mountains, the storm brief and Surely on your wrist."}],"nextVersion":{"label":"Sommet 1.0","means":"Sommet 1.0 is the day the first correction learned from stations beats today’s forecast across a whole region, on stations it has never seen, and goes live there. It ships on a grade, not on a date."},"story":[{"date":"2024","when":"2024","title":"A week in Niseko","text":"Checking the forecast apps every day of a ski week, and finding them generic. The idea starts there."},{"date":"2025","when":"2025","title":"Snowdata is founded","text":"Built for our home mountain, Limone Piemonte: rain in the village, snow on top, and lifts that close in the wind."},{"date":"2025-11-27","when":"27 Nov 2025","title":"The first records","text":"Limone’s snow reports logged several times a day, to compare what was forecast with what fell."},{"date":"2025-12","when":"Dec 2025","title":"The resort database","text":"Resorts entered one by one, each with its base and summit height."},{"date":"2026-01-08","when":"8 Jan 2026","title":"Every model, every height","text":"Each weather model’s forecast stored at base and summit, so each could be scored against what fell."},{"date":"2026-01-15","when":"15 Jan 2026","title":"snowsure.ai","text":"The first version of the website."},{"date":"2026-03-21","when":"21 Mar 2026","title":"Graded every morning","text":"Every forecast scored against measured snow, every day since."},{"date":"2026-05-24","when":"24 May 2026","title":"The measured-snow record","text":"Snowfall measured at weather stations, archived as the yardstick every forecast is held to."},{"date":"2026-09-01","when":"1 Sep 2026","title":"Every station, every hour","text":"Readings from every station we follow, kept hour by hour."},{"date":"2026-09-22","when":"22 Sep 2026","title":"Like with like","text":"A forecast is graded only against a station near its own height, never one in the valley below."},{"date":"2026-10-09","when":"9 Oct 2026","title":"Graded as published","text":"The forecast scored exactly as readers saw it, not as it was rebuilt later."},{"date":"2026-10-29","when":"29 Oct 2026","title":"Sommet","text":"The engine gets its name, and starts learning from the stations: every model captured at 1,700+ stations each morning, in testing."},{"date":"2026-11-12","when":"12 Nov 2026","title":"Sommet 0.9","text":"This page, and its public record at /api/v1/sommet."}],"hero":{"resort":"Limone Piemonte","heights":[{"band":"summit","label":"Summit","m":2085},{"band":"mid","label":"Mid-mountain","m":1548},{"band":"base","label":"Village","m":1010}]}}