Final answer:
Drowning can occur very quickly under various circumstances, from shallow water accidents to natural and infrastructural disasters. The severity can range from isolated domestic incidents to widespread catastrophes as seen in global incidents involving floods and structural failures leading to significant loss of life.
Step-by-step explanation:
The time it takes for people to drown in water can be very short, depending upon various circumstances. Tragically, it's been known that individuals, particularly those who are inebriated or under the influence of drugs, have drowned in as little as 30 millimeters of water. Furthermore, accidents in domestic settings such as bathtubs, buckets, and toilets have led to numerous drownings, especially among children.
Natural disasters and infrastructural failures can also be catastrophic. For instance, faulty storm levees that were not built to adequate safety specifications contributed to the flooding and subsequent death of 1,500 people in New Orleans. Similarly, a landslide that caused a dam to overflow led to the flooding of villages and the death of around 2,000 people.
In regions prone to severe weather and climatic events, such as Bangladesh, the impact of flooding is heightened. Here, a three-foot rise in sea level has the potential to flood half of the country, a terrifying prospect given that a previous cyclone resulted in as many as 150,000 deaths.