Mountain and Parks changes
In June 2021, MetService made changes to forecast pages for New Zealand’s Mountains and Parks on metservice.com and the New Zealand Weather app, which includes the introduction of Mountain weather hazards.
MetService introduced mountain weather hazards across all New Zealand mountain and park forecast areas on metservice.com and the New Zealand Weather app. Mountain weather hazards will be issued daily, identifying weather related risks when threshold levels for wind, wind chill, rain, snow and thunderstorms are met.
The six-hourly manually edited data for locations that were available within the mountain and park forecast area has also been replaced with three-hourly model data updates.
Specific wind speeds are now included in the forecast information issued by MetService; these better demonstrate how wind changes at different heights across a park. The various wind heights were selected for each mountain area to highlight the more popular, and more high-risk altitudes.
Why introduce weather hazards?
The change fundamentally supports the purpose of MetService: To help people stay safe and make informed decisions, based on the weather.
Some common risks in the great outdoors include falls, rivers and hypothermia, which can be affected by weather conditions. MetService is introducing weather hazards for five types of phenomena relating to the weather within mountains and parks.
What are the mountain weather hazards, their thresholds, and the impact?
Wind speeds of above 65km/h.
Gale force winds can make movement harder and more tiring. The strongest winds are most often experienced on ridgetops and through saddles. If wind speeds rise to severe gale, walking can become impossible with a high risk of being blown over. Expect travel times to increase in challenging wind conditions.
50mm+ of rain in 12 hours.
Heavy rain can cause rivers to rise and make river crossings more challenging and dangerous. Being wet may increase the risk of hypothermia - especially if it is windy. Pack adequate wet weather gear.
Wind chill of -10C on a dry day, OR wind chill of less than 0C on a day with precipitation.
Strong winds combined with cold temperatures can dramatically reduce body heat. This can occur even on a fine day and adequate clothing is essential to lessen the risk of hypothermia.
When snow is forecast at, or below, a significant altitude specific to each MetService mountain forecast area.
Snow can dramatically reduce visibility, especially combined with strong winds, creating blizzard conditions. When snow lies on the ground, track following can become difficult and at times, impossible. Walking through snow is arduous and travel times are likely to increase. Snow can make you wet and cold. Loss of body heat may cause hypothermia.
When a high or moderate risk of thunderstorms covers some, or all, of a mountain or park forecast area.
Thunderstorms can produce torrential rain, dramatically increasing the risk of flash flooding, especially in narrow creeks and canyons. Lightning is a significant hazard, especially to individuals on exposed areas. Seek shelter (but not under trees) when thunderstorms are in your area.
MetService have issued a mountain weather hazard, what should I do?
Mountain weather hazards were established to help people best prepare themselves for the outdoors and the expected weather conditions. A weather hazard aims to encourage a user to look closely at the forecast for that area. It may act as the prompt needed for a user to consider their experience and the likely impact of the weather conditions on their trip, whether to pack more gear, plan an easier journey, or to assess if the forecast conditions are appropriate for their level of experience.
Does a mountain weather hazard vary to a Severe Weather Watch or Warning?
Yes it does. Weather hazards are provided in addition to severe weather watches and warnings. Due to increased risks in mountainous terrain, the threshold for MetService issuing a weather hazard are often lower than official MetService Severe Weather Watches and Warnings thresholds. Weather hazards also cover a greater volume of the impacts of the weather, including wind chill.
Weather hazards are only issued in mountain forecast areas (not ski field forecasts). A qualified meteorologist with specialist training in New Zealand's mountain meteorology will issue and monitor the hazard and situation. Weather hazards for the twelve mountain and park forecast areas will be issued daily - early in the afternoon, covering that day, tomorrow and the next day.
Severe Weather information will always be displayed above weather hazards.
What else should I know about mountain weather hazards?
If a hazard threshold is met within a mountain forecast area, the hazard icon will appear. 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 the wind at lower elevations may be considerably lighter. If a weather hazard is triggered, MetService encourage users to prepare for the expected conditions and check the forecast information in more detail.
Hazards are only issued to cover the current day, the following day, and weather hazards for the following day will be added early each afternoon.
What about changes to wind information?
In conjunction with industry groups, MetService have established set wind heights for the mountain forecast areas of most use to those within the area. The intent is to select heights which help users be aware of the risks when crossing ridges or passes, as opposed to reliance on 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 wind heights in each mountain or park forecast area?
|Tararua||1000m and above|
|Paparoa||1000m and above|
|Canterbury High Country||1000m||2000m|