What´s the Temperature? - Norseman

What´s the Temperature?

As Norseman is coming closer, there are lots of talk about the temperature. Here I will explain our thoughts around temperature, both in the water and in the air. Beware, there will be some geeky stuff!

Published: 22.Jul.2019

By: Jørgen Melau
Safety Director Norseman
PhD candidate, Cold Water Swim Research

Norseman is xtreme. We are aware of that, and so are our athletes, this is why they sign up. That does not mean that we don’t care how cold it is. We do. In fact, the significant recourses on we´ve over the years put down on research at Norseman, started because of a cold swim in Eidfjord. In the following, I will try to explain how we are aware of the temperature.

Air temperature

There are lots of good forecast for the weather in Eidfjord, as well as everywhere else around the world. However, there are no metrological stations in Eidfjord. There is a station approximately 13 km from Eidfjord, which gives good and reliable data. But you have to understand that the weather forecast for Eidfjord is, a forecast.  It is calculated with data from nearby stations. So, the prognosis is good, but could be wrong. There are lots of good forecast sites, we recommend the Norwegian Meteorological Institute at www.yr.no

Another useful site if you are geeky (as we are..) is NETAMO This site has a cluster of private weather stations that can be seen on the site. There are several stations in Eidfjord, just search in the upper left corner.

As we now have lots of scientists in Eidfjord the week up to the race, we collect our own meteorological data. We use a calibrated instrument (Kestrel 5400 Heat stress tracker) These instruments give us important data before and during the race, as temperature, wind direction, wind speed, dew point, wet bulb globe temperature, humidity, barometric pressure, heat stress and more. (We told you this would be geeky..)   We use this to publish scientific reports after the race, to see if the body physiology is affected by the weather.

 Water temperature

This is probably the most talked about topic for athletes going to Norseman. “How is the water temperature going to be this year?” Norseman is famed for its cold swim. 

What you must understand about the water temperature is two things. First, it varies throughout the swim. You will feel the temperature changing while you are swimming. So, it is not possible to give an accurate measure of the whole swim, because it varies. Secondly, it could change rapidly. It could cool down in a few hours. This is due to currents in the fjord quickly changing along with the tides.

There is a temperature buoy in Eidfjord today, but it is not operated by Norseman.  And we have seen that this buoy has some pretty incredible temperature readings, so for the moment we do not have much faith in it.

Our good friends at Kongsberg Maritime have been to Eidfjord and rigged two water temperature sensors. One at the start line, and one at the rounding bouy at about 3300 meters into the swim. Note that this is a test project, so the temperatures are “unofficial”.

Again, as scientists, we have our own instruments. The week heading up to race day, we will be in Eidfjord with our calibrated water temperature instrument. (Fluke 52) We will do measurements on race day, on several spots in the fjord. These readings will be used for our science projects.

You may already have read our paper about swimming in 10 degrees waters. In the years to come, we will publish several papers from our research at Norseman. Thank you to all that are participating in our studies!

© Alexander Koerner / nxtri.com

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