New electronic signs have been installed on the Tongariro Alpine Crossing (TAC), in a novel use of technology to help reduce people’s exposure to volcanic hazards along the track. The lights can be changed remotely by Department of Conservation staff using cellular technology. If information is received from GeoNet, GNS Science or the new Tongariro Eruption Detection System indicating the volcano is becoming more active or has erupted, DOC staff can immediately change the lights from green to orange or red, indicating increasing danger or track closure.
This is perhaps the first use of such a system in New Zealand, and their installation has facilitated the TAC remaining open during the busy summer season when there may be up to 1500 people on the track on any given day. The lights indicate the level of volcanic risk affecting the track and its affect on the status of the track i.e. whether the track is open or closed. It’s usually impossible for people to tell beforehand what the level of volcanic risk is, so the lights tell them. They can then make their own decisions about whether to proceed or turn around before they get into the volcanic hazard zones around the active craters.
Similar light sign systems are in place on a few active volcanoes elsewhere in the world where large numbers of visitors or residents are at significant risk. One notable example is Aso volcano in Japan where thousands of tourists may drive or travel in a gondola to the rim of the active vent each day. The lights in the gondola base station and on the crater rim advise people of the amount of sulphur dioxide gas in the air.
On the Tongariro Alpine Crossing the electronic light signs have been located in four places. Triple lights (red, orange and green) have been placed in the Mangatepopo and Ketetahi car parks at the entrances to the Crossing. Green means the volcanic risk is normal (not zero), and orange indicates the risk is elevated. Red means the risk is high, the track is closed and people should turn around and leave the area. Smaller single red lights signs with “Don’t walk” symbols are located at the boundary of the Active Volcanic Hazard Zone around the Te Maari craters that erupted in August and November last year. These activate only at times the track is closed.
The electronic lights are powered by small solar panels and batteries, and information on the lights status is posted on the webpage www.doc.govt.nz/volcanicrisk. Users should visit this page for more information on the lights and all aspects of the volcanic risks in Tongariro National Park.
An important note is these lights have nothing to do with the weather. The track is never opened or closed due to weather or snow conditions. People are aware of the weather and can get weather and avalanche forecasts. Therefore they must make their own decisions about the wisdom of walking the track if alpine conditions are too harsh or uncertain.