Deflections on an Ice Bridge

So when you want to get across a river and there isn't a bridge (and it's winter), and you know how, you build an Ice Bridge. To figure out how much heavy a vehicle you can take across you do a deflection test. Basically you take a heavy thing, put it on the ice and you measure how much the ice deflects under the weight and how quickly. Things that sucked about this are as follows, it was damned cold (-36), there was a wind (making it colder), you had to measure ice deflections every 15 minutes, for 6 hours. It is hard to stay warm when looking through a level made of metal that you freaking eyelid sticks to when looking through the eyepiece. Thing that was good about this was the Alberta Grade AAA steak afterwards and seeing Vicky David for dinner.