There are other natural hazards besetting the animals of the bush. Australia is not a kind land climatically, and every year, every season is likely to bring some kind of natural disaster to one or several parts of the wombat's range.
Flooding, as has already been mentioned, is one of the major disadvantages of burrow life. Most burrows collect some water in their entry way during heavy rain. In poorly drained soils this may make the burrow temporarily unusable, but rainwater rarely fills a burrow to the extent of trapping the occupant. However, burrows dug on the lower banks of creeks or rivers during dry or normal years are almost certain to be flooded at some time. Whether the occupants have sufficient warning to escape these potential death-traps depends on the rate at which the water level rises. A flash flood, caused by a sudden abnormally heavy downpour in the catchment area, can produce a rise of a couple of metres in a matter of minutes; if this happened in the daytime there would be little chance of escape for wombats sleeping in their burrows.
Heavy rain can also result in the collapse of part of a burrow's roof or walls. In any underground construction there is the risk of a cave-in, and wombat burrows probably have minor earth slips fairly frequently. During his explorations of burrows, Peter Nicholson often found small cave-ins 'where the wombat could easily get out by climbing over the dislodged earth'; but during the winter he 'found four burrows blocked by dirt and from only one of these did the wombat dig free'.
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