The Bureau of Meteorology says the stick needed something to measure after Kosciuszko snow depth hit zero and El Niño kept every night in Australia warm.
The Bureau of Meteorology has moved the Kosciuszko snow gauge into a Jindabyne service station freezer after it read zero all September. Dr Petra Voidwell explains why fourteen millimetres of freezer frost is the only number from Australia's second hottest September worth losing sleep over.
The snow depth gauge at Kosciuszko national park spent Friday inside a chest freezer at a service station in Jindabyne. The Bureau of Meteorology moved it there on Friday morning. The gauge had read zero for most of September. A gauge that reads zero is a stick.
I ran the study that recommended the move. My team tested the stick in fourteen places. The freezer won. I will explain how, and then I will explain why it matters more than anything else that happened last month.
The part you already know
Australia had its second hottest September on record. The night-time lows were the hottest for any September since the record began in 1910. That is a long record and it was broken. I do not have much to add. You can read the figures if you want them.
Every state landed in its top five warmest Septembers. The Northern Territory came sixth. It can try again next year. The models said this would happen and it happened. There is nothing in it for a scientist. It is a sum that came out right.
El Niño made it worse. El Niño is a patch of warm sea in the Pacific that pushes heat onto Australia. It is doing that. Global heating is the other half, and it is doing what it does too. Both are proceeding on schedule. I have filed them under routine.
The part that kept me up
On Friday afternoon the gauge recorded fourteen millimetres of frost on the inside wall of the freezer. That is fourteen millimetres more than the mountain managed all month. We read it four times. The chance it was luck is small. I checked that too.
Fourteen is also our sample size. A sample size is how many things you measured. Fourteen is small. I say that now so nobody has to say it to me later.
We kept a second stick on the mountain as a control. A control is the thing you leave alone, so you know what moving the other one did. The control stick measured air. The air was warm. The control is fine, in the way an empty car park is fine.
The gauge has a job description. It says snow. We found it a workplace where snow occurs.
That is Gavin Threlkeld, who speaks for the Bureau on alpine matters. He told me the move was temporary. He also told me the freezer runs at minus eighteen, which the mountain has not done in some time. He did not say what temporary means. I did not push.
Reaction
Lorraine Pike manages the service station. She has put the gauge between the party ice and the frozen peas. "Customers have been asked not to lean on it," she said. "One man asked if it was for sale. It is not. It is the official reading for the whole range."
The ski resorts have taken it harder. A lift operator at one of them, Dean Farrow, asked me whether the freezer accepts season passes. I told him that was outside the scope of the study. He said everything is outside the scope of the study. I wrote that down.
A colleague of mine, Dr Hannah Okonkwo, raised the finding that worries me most. If a freezer counts as a snow station, then every freezer counts. Australia has millions of freezers. That gives Australia millions of winters, none of them outdoors.
"The country would record its deepest snow season ever," she said. "It would all be in kitchens. The Bureau would have to issue an avalanche warning for the frozen section." She did not laugh when she said it. Neither did I.
The careful part
I should be clear about what the study does not show. It does not show that the mountain is cold. It shows that a box in a shop is cold. Those are different findings. The second one is true because someone pays a power bill.
We also could not rule out the ice bags. Frost near the ice may not be weather. It may be ice. Science is mostly telling those two apart, and on Friday we could not. The hedge stands.
Still, the number is fourteen. Fourteen millimetres of frozen water, logged by a government stick, inside Australia, in the warmest spring nights on record. I have run the figures. I have run them again. Nothing I did made it go away.
What happens next
Next September the stick goes back up the hill. If snow falls, it will measure snow. If snow does not fall, Lorraine says the freezer is free until the Christmas rush.
The thermometer stays on the mountain either way. It has plenty to do. The last I checked it was working overtime, and nobody had to move it anywhere.
