From Fire to Flood

This is a short precise of a fire, the recovery period and beyond. The story is depicted in photographic form following the path of a fire caused by a lightning strike.

These lightning strikes are about one hour old, overnight they will grow into fires of more than 100 hectares in size. They are difficult to contain becuase they may be quite some distance off roadways or tracks. Under the right conditions many will be contained by helicopter rappel crews flown into the fire site, these men and women will cut a fire break around the fires perimeter to contain the blaze. Other fires can be contained by ground crews where they have the opportunity to be able to deploy machinery such as bulldozers and graders, of varying sizes, fire trucks, and slip-ons, small four wheel drive vehicles that are the forestry divisions workhorse; and on other occasions tractors, (grass) slashers, and rotary hoes may be the go. Other items deployed in a direct attack are the water knapsack, and rackhoe; plus all the above are at anytime required supported by water bombing aerial attack aircraft, and helicopters.

Fires can burn for hours, days, or weeks, before finally being brought under control, generally by sheer hard work; that is fire crews working rosters of twelve hours on and twelve hours off. Sometimes the fire crews are assisted by the prevailing weather patterns such as light winds, showers or rain; but the later can be diasterous if to much rain falls over the fire area washing the grounds bare of dirt and seed, as depicted in the photographs below.





Thunderstorms and there associated cells can produce extremely heavy localised rains that can be measured in tens of millimetres (ie50/100+) over a very short period of time. This can and does cause enormous damage to the fire area, washing away the fertile soils essential for the growth of all bush plants, flowers, and trees and the like; as the loose ash and soils move down the slopes picking up volume and speed, the water will dam up, overflow, and so go on, eventually creating little creeks of more energy that will ultimately create severe soil erosion; which will help pick up and then move on small and larger branches, to trees of great size that will flow on downstream to yet cause further damage .

The above photographs were taken about three kilometres north of the GLencairn turn off, twelve months after the great alpine fires of December 2006. Hot northerly winds created this situation. The photo on the right was taken using a telephoto lens, here the reader can clearly see no growing ground cover to help bind the soil together.










Severe flood damage

The End.