Flying through a cloud of volcanic ash poses a significanthazard to airlines.
飞过密布火山灰的云层，对航空公司构成了极大的威胁。
2
The natural damming of rivers by landslides is a significanthazard in many areas. Landslide damming is particularity common in mountainous regions.
崩滑堵江事件在世界范围内，尤其在山区广泛存在。
3
Initial nuclear radiation will be a significanthazard with smaller weapons, but the fallout hazard can be ignored as there is essentially no local fallout from an air burst.