struck by lightning each year in Britain, and on average, 3 (5-10%) of these strikes are fatal." In 2015 it was reported that between five and ten deaths from lightning occur in Australia every year with over 100 injuries occurring. It has been reported that "A direct strike accounts for only 3 to 5 per cent of all injuries and death, while ground currents, which spread out over the ground after lightning strikes, account for up to 50 per cent... ...Where the lightning strikes the ground, the ground becomes highly electrified and if you're within that area of ground electrification..." you can receive an electrical shock from the lightning. It was estimated that "...one in four people struck by lightning are sheltering under trees." Effect on nature Impact on vegetation Trees are frequent conductors of lightning to the ground. Since sap is a relatively poor conductor, its electrical resistance causes it to be heated explosively into steam, which blows off the bark outside the lightning's path. In following seasons, trees overgrow the damaged area and may cover it completely, leaving only a vertical scar. If the damage is severe, the tree may not be able to recover, and decay sets in, eventually killing the tree. In sparsely populated areas such as the Russian Far East and Siberia, lightning strikes are one of the major causes of forest fires. The smoke and mist expelled by a very large forest fire can cause electric charges, starting additional fires many kilometers downwind. Shattering of rocks When water in fractured rock is rapidly heated by a lightning strike, the resulting steam explosion can cause rock disintegration and shift boulders. It may be a significant factor in erosion of tropical and subtropical mountains that have never been glaciated. Evidence of lightning strikes includes erratic magnetic fields. Electrical and structural damage Telephones, modems, computers, and other electronic devices can be damaged by lightning, as harmful overcurrent can reach them through the phone jack, Ethernet cable, or electricity outlet. Close strikes can also generate EMPs, especially during "positive" lightning discharges. Lightning currents have a very fast rise time, on the order of 40 kA per microsecond. Hence, conductors of such currents exhibit marked skin effect, causing most of the currents to flow through the outer surface of the conductor. In addition to electrical wiring damage, the other types of possible damage to consider include structural, fire, and