Why is drain dug around the tent in mountains by mountaineer?

Mountaineers dig drains around their tents in the mountains to manage water runoff and prevent flooding. This is especially important in areas with snowmelt or heavy rain, as it helps divert water away from the tent's base, keeping the interior dry. Additionally, it reduces the risk of soil erosion and maintains a stable campsite. Proper drainage enhances safety and comfort during their expedition.