What are dangers of flooding?
The primary danger from a hurricane is flooding. Hurricanes produce torrential rain over long periods of time, which can cause catastrophic floods. In coastal areas, the hurricane's winds drive ocean water onto land in what is called a storm surge, causing potentially devastating coastal flooding. Hurricane winds are dangerous in and of themselves. While rarely as destructive as the winds of a tornado, hurricane winds can often bring down weak structures and trees, which can…
Dangers that are encountered during a tornado: Extremely powerful, rotating winds Flying debris Falling trees Collapsing buildings Dangers found in the aftermath of a tornado: Downed power lines Broken glass and other debris on the ground Structures left structurally unsound Gas leaks and resulting fires. Dangers that may be encountered during a tornado that are not directly related: Strong thunderstorm winds Large hail Lightning Flash flooding Low visibility
Tornadoes produce extremely powerful winds capable of destroying buildings. With those winds come the dangers of flying and falling debris, collapsing buildings, falling trees, and downed power lines. Tornadoes occur during severe thunderstorms and so may be accompanied by other hazards not related to the tornado itself. Such dangers include strong, non-tornadic winds, large hail, lightning, flooding, and poor visibility
Lightning strike and subsequent eletrocution, fires started due to lightning strike, then all dangers that can follow from a fire. Trees, masts, part of buildings falling as a result of lightning strike. Strong winds can damage buildings and topple trees. Heavy rains can cause flooding, with all those associated dangers.
I assume you meant building a railway tunnel under the sea bed? In which case, even with the modern tunnelling technology of today, rock falls, sudden flooding, methane gas, injury and death caused by the machinery, all are possible dangers. Careful monitoring and safety procedures strictly enforced help to reduce the chances of danger to life and limb.