MetService has introduced a weather hazards feature to its mountain and parks forecasts so outdoor users can better plan their trips. Wilderness discusses the changes with Melanie Graham.
In the lead up to winter, MetService has made some changes to the mountains and parks pages on metservice.com. These include the addition of weather hazards across all MetService mountain and park forecast areas.
Melanie Graham, MetService’s public weather services manager, tells us what’s changing.
Why introduce weather hazards?
Some common risks outdoors include falls, rivers and hypothermia and these risks are all elevated in adverse weather conditions. MetService has worked alongside those in the mountain safety sector to identify ways our forecasts can better highlight the possible impact of the weather on a tramping trip; it helps people stay safe and make informed decisions based on the weather.
What should someone heading into the outdoors do when a weather hazard is active?
Weather hazards will help people better prepare for the expected weather conditions. They are not a replacement for MetService severe weather watches and warnings and should not discourage people from going tramping.
A weather hazard should prompt people to consider their plans and the likely impact of forecasted weather conditions. Perhaps packing more gear, planning an easier journey, or choosing a different area.
What is the difference between weather hazards and severe weather warnings?
Weather hazards are provided in addition to severe weather watches and warnings. Because of increased risks in mountainous terrain, the threshold for MetService issuing a weather hazard is generally lower than official MetService Severe Weather Watch and Warning thresholds.
Weather hazards will only be issued for mountain forecast areas and cover a greater span of the impacts of the weather, including wind chill. When thresholds are met, weather hazards for the 12 mountain areas MetService forecast for will be issued daily, early each afternoon, covering that day and the two days following. Severe weather information will always be displayed on mountains and parks pages on metservice.com and the MetService app.
If a weather hazard is active within a mountain forecast area, will I experience these conditions?
Not necessarily; the forecast areas of some of the parks are very large. But if a MetService meteorologist deems a hazard threshold is met within any part of the mountain forecast area, a hazard icon will appear on metservice.com. This doesn’t mean that all park users will experience these conditions. For example, a wind hazard may be active at higher altitudes within a park, but wind speed at lower elevations may be much less.
The weather hazard is a prompt for those checking forecasts to prepare for the expected conditions and check the forecast information in more detail.
Has anything else changed?
In conjunction with mountain safety industry groups, we’ve established set wind heights for the MetService mountain forecast areas that are of the most use to those within the parks. The intent was to select heights that help users be aware of the risks when travelling along ridges or crossing passes, as opposed to spot locations. Spot forecast information for over 50 sites across the mountains and parks network will remain, but the wind data is being replaced with more meaningful wind forecast information that better covers the whole park area.
What are the weather hazards and their thresholds?
- Wind: Gale wind speeds above 65km/h.
- Rain: 50mm+ of rain in 12 hours.
- Wind chill: Windchill of -10° on a dry day, or windchill of less than 0° on a day with precipitation.
- Snow: When snow is forecast at, or below, a significant altitude specific to each MetService mountain forecast area.
- Thunderstorms: When a high or moderate risk of thunderstorms covers some, or all, of a mountain area.