Teacher's Guide

Avalanches - calculating safe travel

A suggested competence aim: 'Avalanches - calculating safe travel'

  • Competence aim

    A suggested competence aim: “Avalanches - calculating safe travel”

Where there is a risk of avalanche, you can use a map and mathematics to work out the safest route through the terrain.

The three-times rule

If you are 500 metres below the top of a mountain where there is a risk of avalanche, you must be three times as far away, that is 1500 metres from the top, to be completely safe.

Illustration: nyhetsgrafikk.no CC-BY-NC-SA-4.0

Illustration: nyhetsgrafikk.no CC-BY-NC-SA-4.0

Task

A skier is standing at the red arrow on the map and is on a trip along the dashed route that continues round Halletjørne. The ice on the water is safe, and the skier wants to go straight across the water to save time.

It looks as though there may be a risk of avalanche on the mountainside Nattane.

Use the information above about the three-times rule to work out the route the skier should follow in order to avoid being in the danger zone in the event of an avalanche.

On the map, the contour interval is 50 metres.

a) Draw an auxiliary diagram of the mountain with measurements.

b) Calculate the runout angle.

Image: Statens kartverk

c) How far from the mountain should the skier go? Use the information above.

d) Work out the runout angle if you follow the three-times rule.

e) Will the skier cross the water safely with regard to avalanche?

Suggested solution:

Snøskred - Matematikk 1P-Y - BA - NDLA

Next steps

Learn more

Text: Elisabet Romedal, NDLA (CC BY-SA)