How RWIS alerts work
RWIS alerts fall into two categories:
1. Sensor-based alerts
Generated using live data coming directly from your RWIS station (air temperature, pavement temperature and battery voltage).
2. Forecast-based alerts
Generated using weather forecast data for the ZIP / postal code configured for your site.
Alert definitions
Alert name | Data used | When this alert is sent |
Air Cooling to Freezing Temp | RWIS air temperature | Sent when the median air temperature over the most recent readings drops to the freezing threshold. |
Air Warming to Freezing Temp | RWIS air temperature | Sent when the median air temperature over the most recent readings rises to the freezing threshold. |
Pavement Cooling to Freezing Temp | RWIS pavement temperature | Sent when the median pavement temperature over the most recent readings drops to the freezing threshold. |
Pavement Warming to Freezing Temp | RWIS pavement temperature | Sent when the median pavement temperature over the most recent readings rises to the freezing threshold. |
Battery Saver Active | RWIS battery voltage | Sent when the device voltage drops and the RWIS station automatically enters battery-saver mode. |
Battery Critically Low | RWIS battery voltage | Sent when the device voltage reaches a critically low level. |
Snow in Short-Term Forecast | Weather forecast (site ZIP / postal code) | Sent when snow is forecast within the next 4 hours. |
Snow in Long-Term Forecast | Weather forecast (site ZIP / postal code) | Sent when snow is forecast within the next 24 hours. |
Weather Event in Short-Term Forecast | Weather forecast (site ZIP / postal code) | Sent when a weather event is forecast within the next 4 hours. |
Weather Event in Long-Term Forecast | Weather forecast (site ZIP / postal code) | Sent when a weather event is forecast within the next 24 hours. |
Freezing Temperature in Short-Term Forecast | Weather forecast (site ZIP / postal code) | Sent when freezing temperatures are forecast within the next 4 hours. |
Freezing Temperature in Long-Term Forecast | Weather forecast (site ZIP / postal code) | Sent when freezing temperatures are forecast within the next 24 hours. |
Short-term vs long-term alerts
Short-term alerts
→ look ahead 4 hoursLong-term alerts
→ look ahead 24 hours
Important notes
Sensor-based alerts use live measurements from your RWIS station.
Forecast-based alerts use the weather forecast for the ZIP / postal code assigned to your site.
Alerts are based on median values across recent readings to reduce false triggers caused by short-term spikes.
You may receive both a short-term and long-term alert for the same condition if it appears in both forecast windows.
Why you may receive multiple alerts for the same condition
For example, if snow is expected later today:
You may first receive Snow in Long-Term Forecast (within 24 hours).
As the event gets closer, you may then receive Snow in Short-Term Forecast (within 4 hours).
This is expected behavior and helps teams plan earlier and then take action closer to the event.
Need help?
If you believe an alert is triggering incorrectly or you would like to adjust your alert configuration, please contact Viaesys support at [email protected].