Strong winds on kunanyi/Mt Wellington in southern Tasmania on Wednesday would have shut down the proposed Mt Wellington cable car.
Bureau of Meteorology observation data from Wednesday reveals that for much of the day wind gusts in excess of 100 kilometres an hour were common with a gust of 156 km/h recorded at 2.30pm. The wind direction swung around between west south west and west north west.
With significant variations in wind speed within a short period of time, it is likely that a cable car would have been forced to shut down for the bulk if not all of the day.
Last week Tasmanian Times asked Mt Wellington Cableway Company executive director Adrian Bold at what wind speed the cable car would have to be closed. Bold stated that on the second leg the cable car could “safely and comfortably operate in winds up to and sometimes in excess of 100 km an hour”. The direction of the wind, he added, “is equally important” to the wind strength.
On its website, the MWCC claims that its preferred cable car “offers incredible reliability of up to 120km/h cross winds”.
The notional plans developed by the Mt Wellington Cableway Company (MWCC) comprise two separate cable car systems: the first from Cascade Gardens to Golden Gully on the ridge above Old Farm Road and the main cable car from Golden Gully to the summit.
On the lower 1 kilometre leg it is proposed to use small 8-seater gondolas. On the upper 3.6 kilometre leg the MWCC states that it is “considering” using two 60-seater double-decker cabins, with the top deck open to the elements.
What percentage of time the proposed cable car would be grounded due to wind speed is unknown.
According to Bold “preliminary wind studies” for the MWCC indicate that, “suspensions due to wind affecting the proposed route will be minimal and within industry best practices.” What constitutes “minimal” and “within industry best practice” is unclear.
On its website the MWCC states that wind speeds in excess of 120 km and hour account for “less than 0.5% since 1961 on the eastern slopes.”
Phil Harris, the Director of the adventure travel company Aardvark Adventures told Tasmanian Times that he thought the wind speed threshold for shutting the cable car down would probably be far lower than 100 km an hour and closer to 60 or 70 kilometres an hour. Harris, who has extensive experience in the skiing and adventure travel industry, said that wind “any higher than that is likely to start becoming quite uncomfortable for passengers.”
He also expressed concern about how a rescue operation would be mounted, especially in extreme weather conditions. “You have to plan for the worst case scenario because at some stage it will breakdown ... then it becomes a matter of getting all the people off in a specified period,” he said.
Wind speeds lower than the MWCC’s thresholds of 100 or 120 km/h or the combined effects of wind and rain would be likely to reduce the carrying capacity of the system. With low temperatures and even moderate wind speeds the wind chill factor would be significant, Harris said. He doubts many customers would opt for the exposed upper deck in poor weather. “Why would anyone go upstairs if it was six degrees and the wind was blowing 60 kilometres an hour?”
On Sunday and subsequently the MWCC’s Facebook page highlighted the temporary road closures due to snow and the volume of cars. However, on Wednesday the company’s Facebook page made no mention of the possibility that high winds would occasionally force the proposed cable car to be shut down.