Behind the scenes: river ice break up predictions
Kate Humble and the 23 Degrees team are back after filming the break up of the ice at Alexandra Falls in Hay River in the northern territories of Canada. This was a job for people with strong nerves and infinite patience.
You see the problem with filming weather phenomena is that you never quite know when they are going to happen. It's true scientists can track weather events like storms with radar and satellites but even then, it can change direction at the last minute and you will miss it.
It's the same with filming the ice break up. The scientists have been taking readings, comparing the ice build up with previous years, but this kind of prediction is not an exact science, so they can only narrow it down to a rough window that they think it will break up in. This year all was going to plan and they thought it would go in late April; we mobilized in the UK to head out, but then there were a few cold days so they had to start again with their predictions and we had to postpone our flights.
At times it can be very frustrating, because the team have to work out when's the right time to go. If they head out too early, they'd be hanging around waiting and waiting, and would not be able to afford to stay long enough to get the collapse of the frozen waterfall. Head out too late and the break up could happen while they were 35,000 feet over the Atlantic.
As it happens the team got it just right and arrived in good time with the scientists saying it would break up in the next few days of their arrival. Then it was a waiting game, a case of heading out to the frozen waterfall and listening for the first cracks. On our first day of filming not much happened and after ten hours of waiting they headed back to base praying it wouldn't happen overnight in the dark.
On the second day of filming after several hours of waiting and nothing happening, the Assistant Producer had to head off for another bit of important filming. 5 minutes after she left the falls started to break up. Two months of planning, days of waiting and she missed the lot. However the director had had his cameras trained on the falls and got the collapse in all its glory.