At least five are dead, and more than 150 were injured following a lightning disaster atop mountains in southern Poland and Slovakia on Thursday.

The incident took place at the peak of Giewont, a 6,217-foot-tall summit in the West Tatra Mountains. The mountain range cuts through extreme southern Poland and Slovakia, before curving through Ukraine and tracing an arched spine through Romania and Serbia. Giewont, less than a mile from the Slovakian border, is one of more than 70 mountains in Poland topping 6,000 feet in elevation.

At least four hikers were reportedly killed at the summit by a lightning strike. A fifth person perished several miles south of the border in Slovakia, where ABC News reports a Czech tourist was knocked off Banikov peak by a lightning strike. The man then plummeted several hundred yards down the mountain. According to Reuters, his female companion was injured.

Atop Giewont’s summit stands a nearly 50-foot iron cross, which can focus gathering electrical charge and help trigger strikes. Two children were among those killed in Poland. Some have speculated that many of the additional injuries may have stemmed from charge or ground current carried through metal chains erected to help tourists climb.

A number of the injured — some critically ― fell after the lightning strike, incurring lacerations, broken bones and head injuries in addition to severe burns.

At least five rescue helicopters were dispatched to various parts of the mountain range in response to the barrage of lightning strikes. Victims were taken to a hospital in Zakopane, about five miles away to the north of the mountain.

While it is easy to blame climbers for being on top of a mountain during a thunderstorm, the reality is far from simple. Even weather-savvy veteran hikers can fall victim to the rapidly shifting weather on mountain peaks.

Eyewitness reports suggest it was sunny at the time of the initial strike, suggesting the storm was quite distant.

Lightning data shows most of the lightning activity in Slovakia, with only a few strikes hitting the ground in Poland itself. That suggests the storm’s core was largely anchored south of the mountain. It may have been an errant positively charged bolt — an extremely powerful bolt that can leap 10 or more miles from a parent thunderstorm — that triggered the fatal strike.