On glaciers, the snow bridges that form above crevasses have hardly been considered by researchers up to now, despite their importance for high mountain activities (skiing, mountaineering) and the risks that their possible failure poses to practitioners. In order to improve our understanding of the formation and evolution of these fragile snow structures, we monitored during two years a succession of three crevasses located at 3450 m a.s.l. in the Mont-Blanc massif (France) using a set of sensors including an automatic camera, air temperature sensors, a wind vane-anemometer, and an extensometer. Geophysical profiles (ground penetrating RaDAR) were also carried out to clarify the glacial context. Despite particularly extreme monitoring conditions, at the level of a bump formed by the bedrock under an ice thickness of c. 25 m, we have shown that a wind event parallel to the crevasse favours its filling by snow while a strong wind making a significant angle with the crevasse under largely negative temperatures can rapidly create a snow bridge by cornice accretion that grows by extending leeward. High temperatures are responsible for most of the natural failures of SBs. These elements are already used for risk mitigation.

在冰川上，形成于裂缝上方的雪桥迄今为止几乎没有被研究人员考虑过，尽管它们对高山活动（滑雪、登山）很重要，而且它们可能失败给从业者带来的风险。为了更好地了解这些脆弱的雪结构的形成和演变，我们在两年内使用一组传感器（包括自动摄像头）监测了位于勃朗峰地块（法国）海拔 3450 米处的三个裂缝。 、空气温度传感器、风向标风速计和引伸计。还进行了地球物理剖面（地面穿透雷达）以澄清冰川背景。尽管监测条件特别极端，但在冰层厚度为c的基岩形成的隆起处. 25 m，我们已经表明，平行于裂缝的风事件有利于其被雪填充，而在大部分负温度下与裂缝形成显着角度的强风可以通过檐口积聚迅速形成雪桥，该雪桥通过向背风延伸而生长。高温是大多数 SB 自然故障的原因。这些元素已经用于降低风险。