Wellington Scoop

Southerly storm warning from Mountain Safety Council

Press Release – NZ Mountain Safety Council
A strong southerly storm is due to create significant snowfall across the country in the next 72 hours.

Mountain Safety Council (MSC) chief executive Mike Daisley is urging caution for backcountry users. “Although this isn’t the first storm cycle this year to bring snow to low levels, it has the potential to create significant issues in the backcountry areas that are unmarked and not managed. What I mean by this is that there are no ‘reduction’ activities done, like controlled blasts, to release any loaded slopes,” he said.

“Therefore, if you’re heading into the backcountry, either via the ski field or self powered, you need to first check the avalanche risks via the NZ Avalanche Advisory (NZAA) in your intended area. Having the equipment and training to use this equipment are the other two important parts that lower your risk of being caught in an avalanche,” said Daisley.

MetService General Manager Corporate Affairs Jacqui Bridges says, “From Tuesday to Thursday, severe weather will affect many parts of New Zealand, including snow, heavy rain, severe gales and large southerly swells. This is a significant and widespread weather event, and we strongly advise people to plan accordingly by staying up to date with the latest forecasts and severe weather information at metservice.com.”

Trevor Streat, IFMGA guide and senior forecaster for the NZAA, is concerned about a possible ‘persistent weak layer’ hazard in some regions particularly with the weight of the new snow, “Weak surface snow can be found in many places right now. Unless this is destroyed by warm temperatures and wind or rain at the start of the storm, we can expect a poor bond at the interface between the new and old snow.”

“This means an increased risk of avalanching during the storm as well as the potential for a longer lived lingering hazard or ‘persistent weak layer’ to develop in those places that do not avalanche’s directly during the storm.”

“It’s always hard to say exactly how things will work out but we’re definitely in with a chance of a developing a ‘persistent weak layer’ situation.”

Nelson lakes NZAA forecaster Matt Wilkinson wants people to note that storm cycles are very much related to increased avalanche danger saying, “The bigger the weather event, generally the higher the risk or danger is likely to be.”

The NZAA is not only a tool for backcountry skiers, snowboarders and mountaineers but also for trampers and hunters. Wilkinson went on to say, “Avalanche danger not only effects popular tramping tracks in the high mountains but also valley floors. So, be aware of avalanche danger even when tramping and hunting in mountains during winter”

The storm conditions are expected to move through to the North Island early Wednesday. Tongariro Forecaster Richard Te Ua predicts danger ratings will be elevated, and that wind slab on the lee slopes is likely to be the primary concern in the North Island. Te Ua said “Cold events such as this bring dry snow which is easily transported by the wind into gullies and lee facing slopes”

Daisley was quick to remind backcountry users to be mindful in the days after the storm that the avalanche risk may stay high for some time.

“What some people possibly misunderstand is that once the storm passes there can be loaded slopes for some time. It does not necessarily mean the risk is lowered if the skies clear up. You need to make sure the NZAA is a key part of your planning,” he reiterated.

“It doesn’t take snow to bury a person and have them totally unable to move. Think back to your days at the beach where you might have buried someone up to the waist. They are incapacitated pretty quickly,” Daisley concluded.

Luke Ochs, NZAA forecaster for Mt Hutt reminds backcountry users that “Regardless of weather, please make sure you and your friends have checked, and practiced with, your respective rescue gear. Please check your forecasts and always seek additional opinions and perspectives. Backcountry travel is amazing, so let’s practice and celebrate safe techniques to continue this activity for years to come.”

About the NZAA
The NZAA – avalanche.net.nz – is a free service that is provided by the Mountain Safety Council. Forecasts are updated daily by professional forecasters in the associated regions as the conditions change.

General Avalanche Safety Information
Videos – What Is The NZ Avalanche Advisory? | Epic TV – Planning And Preparation
Mountain Safety Council Website Resources – Avalanche Safety | Activities – Snow & Alpine


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