This page provides a complete sample response for a winter storm hazard from the Active Hazards API endpoint. Winter storm hazards encompass snowfall warnings, blizzards, and ice storms, and are typically sourced from national weather agencies such as Environment Canada, the U.S. National Weather Service (NWS), and the Australian Government Bureau of Meteorology (BoM). These alerts follow the Common Alerting Protocol (CAP) standard.
Winter Storm-Specific Properties
Incident Data
The incident.properties object for a winter storm contains CAP-based alert metadata describing the weather warning. Key incident properties for winter storms include:
event - The specific weather event type (e.g., "Winter Storm")
headlineDescription - Full descriptive headline combining alert status and detailed forecast information
hazardSeverity - The severity classification of the hazard (e.g., "WARNING")
incidentLocationName - Human-readable location of the alert (e.g., "Corner Brook, Newfoundland and Labrador, Canada")
headline - Alert headline text (e.g., "yellow warning - winter storm - in effect")
description - Detailed alert description with snowfall accumulation amounts and travel impacts
severity - CAP severity level (e.g., "Moderate")
urgency - CAP urgency level (e.g., "Expected, Past")
certainty - CAP certainty level (e.g., "Likely, Observed")
effective / expires / onset - ISO 8601 timing fields for the alert window
msgType - CAP message type (e.g., "Update")
instruction - Recommended actions (e.g., "Prepare for quickly changing and deteriorating travel conditions.")
category - CAP category (e.g., "Met" for meteorological)
Features
The features property contains a GeoJSON FeatureCollection with CAP_INFO features. Each CAP_INFO feature represents an individual alert info block from the original CAP message, containing the alert polygon geometry along with area descriptions and geocodes. Winter storm alerts may also include SMART_ALERT and EXPOSURE_AREA features within the same collection.
Exposure Areas
Winter storm hazards may use multiple exposure levels representing different severity zones within the alert area:
Level 0: Limited exposure area - peripheral zone with lower expected impact
Level 1: Moderate exposure area - core zone with higher expected impact
Sample Response
Note: Coordinate arrays have been replaced with [...] for brevity. In actual API responses, these contain complete GeoJSON coordinate arrays. The incident.properties object has been truncated with "..." to show only key fields. The full response includes additional CAP metadata fields such as note, references, rawMessage, eventCode, and headlineDescription. The features collection includes multiple EXPOSURE_AREA and SMART_ALERT features; CAP_INFO area features (one per alert zone) are also present in the full response but not shown here.
