Feature 2｜ERTAS weather alertsRead Observatory forecasts and issue risk alerts early
Time to stop work, evacuate and deploy
Extreme Weather Alerts
Warnings about 2 hours before a rainstorm, instant alerts when water rises
Combining Hong Kong Observatory SWIRLS nowcasts with on-site water-level sensors, SenseOS assesses risk 24/7 and alerts site teams early to stop work, evacuate or deploy pumps.
- Sump pits
- Open channels
- Construction sites
Powered by SenseOS｜Engineering-grade deployment with 3,000+ devices connected locally
Published Updated
At a glance
What is the ERTAS extreme weather alert?
ERTAS is a rainstorm early-warning service for construction sites, built on the SenseOS platform. It reads Hong Kong Observatory SWIRLS rainfall nowcasts to assess local rainstorm risk about two hours ahead, optionally combines them with on-site water-level sensors, and notifies site teams 24/7 by SMS, WhatsApp, email or voice call so they can stop work, evacuate or deploy pumps in time.
Key facts
- Warning lead time
- About 2 hours before a rainstorm
- Data sources
- Observatory SWIRLS nowcasts, plus optional site water-level sensors
- Alert channels
- SMS, WhatsApp, email and voice call, including an all-clear message
- Sensor battery
- About 8–10 years, depending on upload frequency
- Pricing
- By monitoring points, features and service period, quoted after site assessment
Who it is for
- Construction sites in low-lying areas or near rivers
- Basements, deep excavations and underground works
- Contractors that need defined stop-work and evacuation triggers
- Projects that must keep rainfall and water-level records for review
How it works
- 1Continuously read Observatory forecasts and site water levels
- 2Apply preset risk formulas to set the risk level
- 3Notify assigned recipients with the matching response action
- 4Send an all-clear, then replay history and export reports
Rainfall defence
Warned before the storm, alerted during the flood
- About 2 hours beforeFeature 2｜ERTAS weather alerts
- During the storm
Feature 1｜Live water levelsGraded alerts the moment water hits a threshold
Arrange pumping and drainage immediately
Feature 1｜Real-time water levels
Up to four alert levels, reported instantly
Sensors at sumps, underground passages, low-lying areas and open channels trigger the matching alert level as water reaches each one.
- Very high level sensor
- High level sensor
- Medium level sensor
- Low level sensor
NB-IoT moduleSensor junction box
Readings are sent to SenseOS over the NB-IoT network
- Battery powered
- Wireless
- Battery powered
- Battery life (by upload rate)
- 8–10 yrs
- Battery life (by upload rate)
- Low / medium / high / critical
- 4 levels
- Low / medium / high / critical
- Client system integration
- API
- Client system integration
Feature 2｜ERTAS early weather warning
Decide to stop work or evacuate before a local rainstorm hits
- Reads Observatory SWIRLS nowcasts to assess local rainstorm risk about 2 hours ahead
- Preset risk formulas set the risk level and response actions
- Notifies site managers by SMS, voice call, email and WhatsApp
Data source: Observatory SWIRLS
Weather radar data predicts local rainfall
Notified from alert to all-clear
Messages state the risk level and required actions
How it works
Site water levels plus Observatory forecasts, assessed on one platform
On site
01
Install water-level sensors
Placed at low-lying points across the site
02
Regular monitoring
Status is sent to the server over NB-IoT
Observatory
03
Read Observatory SWIRLS
Weather radar data predicts local rainfall
SenseOS platform・24/7
04
Data combined 24/7
Preset formulas set the risk level and actions
Site managers
05
Instant alerts
SMS, voice, email and WhatsApp, leaving time to evacuate and deploy
Every location on one platform
Web and mobile app stay in sync with live water levels, rainfall forecasts and alert history; reports can be exported for submission. Add more monitoring apps to the same SenseOS platform later.
History replay: review past water-level and rainfall records to refine precautions
Web + mobile app, always in sync
Sensor specifications
Engineering-grade equipment built for sites
Flood sensor
Flygt ENM-10
- Ingress protection
- IP68
- Liquid temperature
- 0–60°C
- Cable length
- 6 / 13 / 20 / 30 / 50 m
- Liquid density
- 0.95–1.10 g/cm³
Transmission
Senso8 LRS20600
- Network
- NB-IoT
- Power
- 1 × 3.6V C-size battery
- Battery life
- 10+ years (60-min upload) ~8 years (10-min upload)
- Upload interval
- 60 min default, configurable
- Integration
- Open API
Where is it used?
Temporary work platformsRiver channel worksExcavationsSump pitsLow-lying sites
Case study
Kai Tak River works｜ERTAS weather warning and water-level monitoring
Platform workers were told to evacuate before the amber rainstorm
Continuous monitoring helps teams act earlier
FAQ
Using Observatory SWIRLS nowcasts, local rainstorm risk is typically assessed about 2 hours ahead.
Preset formulas combine forecast rainfall, accumulated rainfall and site water levels; each level maps to response actions.
Multiple recipients and schedules via SMS, WhatsApp, email or voice call, plus an all-clear message.
ERTAS can run on its own or together with site sensors for a combined assessment.
About 8–10 years depending on upload frequency, with low-battery reminders.
History replay shows past water-level and rainfall records, with exportable reports.
Data can be sent to client or government systems via API, or used standalone.
By number of points, features and service period, quoted after site assessment.
