Green ice?

Apparently the correct term for ice which looks like glass, is “green ice”.

Whilst skating over some incredibly smooth “green ice”, Dave Young decided to poke a hole in it to see how good the visibility was. It then dawned on me that he could attach my ATC2k camera to the end of the pole and record upwards through the ice, so I pulled it out, handed it over, and the video below was the result!

Dave Young poking a hole through the ice with his pole

Alan Knowles standing on perfect 'green ice'

Dave Young standing on some super clear 'green ice'

Rocks as seen through the ice

Attempt at last skate of the season

After Dave Young’s stunning find of ice at the Lower Manorburn dam on August 17th, I decided to do some investigating for the 2011 ice skating season.

After feeling a rather large earth quake at 4:38am, I decided to bust a move up to Swampy Summit, about 9 km from my home in Dunedin. I’ve had a theory for a while now that some of the small ponds up there would freeze in the winter months. We didn’t have any major frosts this winter so I didn’t bother inspecting, but last night there was at least a chill in the air so I figured I’d go check it out to at least confirm if there was any ice whatsoever and if so, how much there was. There was absolutely no sign of frosts anywhere in the suburbs, even up on the hills, so signs were looking highly unpromising for any ice. After dodging a few trees which had presumably been knocked over during the quake, I made my way to the bottom of the access road to Swampy Summit. Unfortunately it is not possible to drive all the way there, so I had to walk up the hill. The walk should have been 4 km in and 4 km out, but I stupidly took a few wrong turns and it ended up being about 13 kms instead! If you make the trip yourself, ensure you take plenty of water as although it’s not a steep climb, you will gain about 650 m in altitude, so it can be a little tiring.

The view from the top was terrific. It was still very early when I arrived (~7:00am) and my cheapo Canon camera struggled with the low light conditions. The temperature was zero degrees Celsius, but there must have been a heck of a wind chill factor as it was blowing a gale up there.

View towards Mosgiel from on top of Swampy Summit

The largest ponds at the summit had no ice on them unfortunately. This was entirely expected though as the temperatures hadn’t been all that cold lately.

The largest pond on Swampy Summit.

However some of the smaller ponds did have sections of ice on them. Not a lot of ice, but enough to at least prove that there is serious potential for skating to be done on the summit (when the conditions are right). The maximum thickness of the ice was about 5 mm, but even the best frozen ponds had only 30% of their surface frozen.

Edge of one of the smaller ponds on Swampy Summit

Ice, but too thin to be useful.

So … there was no chance of skating today, but I’ve at least shown that there is promise of potentially skating up there some time in the future.


After many, many years of trying, I finally got the chance to skate on the Idaburn dam. Ice quality was average, but very thick at least. Kinda weird skating beside a main highway and underneath giant powerlines. I’m not sure why so many people rave about this place at seemed kinda crappy to skate at. Lower Manorburn, Poolburn and pretty much anywhere else I can think of are better IMO.

Alan Knowles and Dave Young on Idaburn dam

The power lines hanging over the Idaburn dam dropped annoying amounts of frost onto the ice.