North-westerly

A light or even moderate north-westerly regime often has little impact on the conditions close to Fiesch. However, it reinforces both the Grimseler to the east and the flow up the main Rhône valley to the west, presenting challenges for pilots attempting flights beyond the local area. A stronger airflow from this direction is more problematic: you may only discover you are a lee behind Eggishorn when you climb out, there may be a sidewind disturbing the thermals at Bellwald, sudden windshears anywhere to the east of Münster, and vicious turbulence to the west of Visp.

The header image on this page was taken during my first example flight below, looking north-east, on my way back from Brig towards the Aletsch area on a flat triangle route. The slant on the clouds from left to right illustrates not only the significant north-westerly airflow, but also how wind speeds from this direction typically increase with height, unlike the Bise, which is stronger at lower levels.

Flight in north-westerly conditions

Flight in north-westerly conditions (click here for 3D visualisation, here for XContest details)

My account of my flight shows how it was affected by the local airflows to be expected in a north-westerly, but half a dozen pilots were able to complete the classic 200k FAI triangle that day!

If you head east in this regime, to fly over the Furka and Oberalp passes, then sooner or later the north-westerly flow is likely to disrupt conditions on the south-facing side of the valley and lead to you to cross over, as in this second example flight:

Flight over the passes in north-westerly conditions (click here for 3D visualisation, here for XContest details)

As a general rule, once you’re on the other side of the valley, it’s likely to be best to stay there.