Flying between moutain tops & glaciers

Hi there.
Are pilots flying routinely at moderate flight levels (around 9000 ft) between mountain tops scattered with high altitude glaciers (around or above 9000 ft), subject to occasional blinding (or have their plane lit up) by strong specular sunlight reflections originating from these high altitude glaciers during sunny and clear sky flights ? And in the affirmative, is it a frequently occuring phenomenon ?
J.F.B.