"You shall not pass," said Gandalf The Grey, a character in the iconic movie trilogy, Lord Of The Rings. In real life, officials warned visitors to stay away from New Zealand's "Lord Of The Rings Volcano" due to a potential eruption.

Mount Ruapehu, which is located at the Tongariro National Park in the North Island, last erupted 9 years ago. The landscape was immortalized in director Peter Jackson's trilogy as the wasteland of Mordor.

New Zealand's Department of Conservation (DOC) issued a warning asking trekkers to steer clear of the Summit Hazard Zone, which is located within 2 kilometers of the Crater Lake's center.

The GNS Science raised the Volcanic Alert Level to 2, which lifted it from "moderate to heightened unrest" due to increased activity.

Since mid-April, the lake's temperature increased to 46 degrees Celsius (115 degrees Fahrenheit) from 25 degrees Celsius (77 degrees Fahreinheit).

"There are more signs of life at the volcano," said volcanologist Brad Scott.

Thousands of people cross the popular "Tongariro Crossing" each year, which is a 20-kilometer (12-mile) passage that allows people to pass three volcanoes near the area.

"We recommend climbers, trampers and walkers do not enter the zone. Guiding companies should also heed the advice and not take people into the zone," said DOC Operations Manager for Tongariro Paul Carr.

Dr. Harry Keys from DOC's Technical Advisor Volcanology added that rivers that drain the Summit Hazard Zone and Crater Lake could suddenly rise.

Keys warned that people who are walking towards the Whangaehu, Whakapapaiti, Whakapapanui and Mangaturuturu streams should be wary of any possible lahar noise from upstream and cross the streams as fast as possible.

The DOC and GNS Science are continuously monitoring the Mount Ruapehu's activity. The DOC has also informed several local government groups including the Ruapehu Alpine Lifts and New Zealand Police about the situation.

Mount Ruapehu is New Zealand's biggest active volcano, which started erupting approximately 250,000 years ago. It has 3 major peaks, namely Paretetaitonga, Tahurangi, and Te Heuheu.

After it became an iconic landscape in The Lord of the Rings trilogy, Mount Ruapehu quickly became a popular attraction among trekkers and movie fans alike.

Photo: Katarina Dzurekova | Flickr