8 October 2026/5 min read
Acceleration, not velocity: the signal that matters
Alpine slopes move all the time. The warning sign is not how fast a slope moves but when it starts moving differently.
- InSAR
- Brienz
- Methods
Satellite triage for alpine hazards
Know which slopes to look at first.
Watchberg screens whole mountain regions with radar satellites, flags the slopes that start to accelerate, ranks them by what lies below, and hands your experts a short, sourced briefing.
Decision support for experts, not a public warning.
Built for the people who carry the responsibility
- Cantonal natural-hazard offices
- Railways and road authorities
- Cable cars and mountain railways
- Hydropower operators
- Hazard consultancies and monitoring firms
The problem in numbers
The signal was there. The system to read it was not.
9 months
Ground motion was visible in L-band radar nine months before the 2025 Blatten collapse.
ESA MODULATE, NHESS 2026
CHF 320m
Total damage from the Blatten rock-ice avalanche of 28 May 2025.
Swiss Insurance Association
2,389
Cable-car and lift installations in Switzerland, most of them in terrain nobody can instrument slope by slope.
Seilbahnen Schweiz
1,100 km
Of the Swiss Federal Railways network is exposed to natural hazards.
SBB
Sources are listed in full in the articles. Watchberg figures are projected and to be validated in the 2027 pilot programme.
How it works
Three steps from satellite pass to expert decision.
No new sensors on the mountain. Watchberg works from satellites that already pass over every slope on a fixed schedule.
- 01
Screen
Every week to month, Watchberg processes Sentinel-1 C-band, NISAR L-band and Sentinel-2 optical data over whole regions: thousands of slopes, not a handful of instrumented sites.
- 02
Detect
Each slope gets its own baseline. The engine looks for the change, not the speed: the onset of acceleration across bands, with explicit confidence and data gaps. A lead time of years to weeks is projected and to be validated.
- 03
Brief
Flagged slopes are ranked by what lies below them, then handed over as a short, sourced briefing: what changed, the evidence, the confidence, what is exposed, and a recommended next step.
The output
A ranked list and a briefing, not a wall of pixels.
Experts do not have time for raw interferograms. Watchberg delivers what changed, how sure we are, what sits below, and what to do next.
Example region, Central Alps
Screening period: 4 weeks
Ranked by exposure
- 01Escalate
North face, rock slope above the valley road2,850 m
Velocity up 3.1x against the 24-month baseline, consistent in L and C band
Exposed: Cantonal road, 2 hamlets, cable-car base station
- 02Watch
Rock glacier, east cirque2,640 m
Seasonal pattern broken: no winter slowdown, offset tracking agrees
Exposed: Hiking route, alpine hut
- 03Watch
Glacier tongue, west side2,400 m
Front thickening, surface change in optical data, L-band coherence low
Exposed: Hydropower intake, access road
- 04Stable
South ridge, talus slope2,300 m
Within its own seasonal baseline for 36 months
Exposed: Forest road
Illustrative data. Status labels and figures are examples of the format, not measurements.
What makes it different
Built for high altitude, not adapted to it.
Built for high altitude
Rock-ice interaction, permafrost, glacier fronts and seasonal snow are the baseline, not edge cases.
Multi-band by default
L-band NISAR, C-band Sentinel-1 and optical Sentinel-2 are fused, because C-band alone loses coherence on snow, ice and fast movers.
Acceleration, not velocity
Glaciers move all the time. The signal is when a slope starts moving differently from its own past.
Exposure-aware ranking
Every flagged slope is linked to what lies downstream: settlements, roads, rail, cable cars, dams.
Expert-ready briefings
A two-page briefing a geologist can read in minutes, every number traceable to a dataset, a date range and a processing version.
Hand-off built in
Every briefing ends with a recommended next step: expert review, drone survey, ground radar, and the partner who can deploy it.
Who it is for
One screening layer, three ways to use it.
Cantonal hazard offices
Cover hundreds of sites with the same team.
- A ranked list of the slopes that changed, every week to month
- Sourced evidence your geologists can take into the hazard commission
- A record of what was screened, when, and with which data
Infrastructure operators
A monitored corridor, not a monitored point.
- Rail lines, roads, cable cars and dams screened end to end
- Early signals that feed your existing escalation procedures
- A projected lead time of years to weeks, to be validated in the pilot
Consultancies and monitoring firms
Know where to send the ground radar next.
- A screening layer before site instrumentation
- Briefings that support, never replace, your expert judgement
- A channel for targeted monitoring mandates
Why now
The data finally exists. Nobody has turned it into a service.
Calibrated NISAR L-band data has been public since July 2026: free, systematic, on a 12-day repeat. Sentinel-1C and 1D image the Alps every six days. Together with Sentinel-2 optical data, the raw material for regional screening is now open to anyone who can process it.
Europe's ground-motion service stops at the Swiss border, and the national C-band product has no measurement points on snow, ice or vegetation. The highest, most exposed terrain in the Alps is the least covered.
In 2025, Blatten showed what late detection costs. Researchers later found the motion in the satellite archives going back years. The methods work. What is missing is a system that screens every slope and tells an expert where to look.
- NISAR L-band
- Public since July 2026
- Sentinel-1C and 1D
- 6-day repeat over the Alps
- Sentinel-2
- 5-day optical revisit
- Swiss coverage in the EU ground-motion service
- None
- ROSE-L (ESA L-band)
- From 2028
Scale
Today the Alps. Tomorrow every mountain range.
The satellites already cover the planet. Sentinel-1 and NISAR image every landmass on a fixed schedule, free and systematic. Detecting the onset of acceleration is terrain-agnostic. What changes from one region to the next is the exposure layer, what lies below, and the expert who receives the briefing.
Watchberg is built in Switzerland, where the data, the users and the ground truth are densest. It is designed to run wherever satellites look.
- 01
The Alpine arc
Six countries, about 190,000 km2 and 14.8 million inhabitants under the same physics. First expansion planned from 2028.
- 02
Himalaya and Karakoram
On 26 August 2026 a glacier collapsed on the Nepal-China border. The warning signs were visible in satellite imagery beforehand. Same physics, far thinner ground monitoring.
- 03
The Andes
Glacier-fed valleys with settlements, mines and hydropower below, and very few instruments on the slopes above them.
- 04
Norway and the fjords
Rock slopes above fjords share the Alpine failure mechanisms, and the same satellites pass overhead every few days.
Every expansion date is planned, not promised. The pilot programme in Switzerland comes first.
Articles
Notes on alpine hazards and satellite radar.
8 October 2026/5 min read
Brienz: 62 weeks away from home and what monitoring costs
Brienz spent 62 weeks without its residents and runs a CHF 3.5 million monitoring programme. Why regions need a screening layer before site monitoring.
- Brienz
- Kandersteg
- Economics
8 October 2026/5 min read
L-band arrives: what NISAR changes for alpine monitoring
Free, calibrated L-band radar from NISAR has been public since July 2026. For snowy, rough and fast-moving alpine slopes, it is the missing wavelength.
- NISAR
- L-band
- Sentinel-1
Join the 2027 pilot programme.
Watchberg is preparing pilots with hazard offices and operators in three Swiss cantons. If you carry responsibility for alpine slopes, let us show you what a weekly briefing would look like for your region.
Pilot programme 2027. In discussion with hazard offices in three cantons.