Lahar alert: 20-minute deadline

Police are providing round-the-clock coverage to ensure a swift response when the Mt Ruapehu Crater Lake overflows, the Ruapehu District Council said yesterday.

The Department of Conservation estimates that a lahar when the crater lake bursts its walls is likely to occur next year.

Recent criticisms from locals that the officers spent their time dishing out speeding tickets were denied by council chief executive ChrisRyan.

Mr Ryan said seven full-time police officers at Waiouru and Ohakune were providing 24-hour coverage to enable emergency services to respond in 20 minutes when the crater lake overflowed.

He said there were many difficulties in planning a response to a lahar.

"Lahars are one of nature's most destructive forces and the one we are waiting on has the potential to be many times larger than the lahar travelling the same route that caused the Tangiwai disaster in 1953 that claimed 151 lives," he said.

"Because the expected lahar event will happen extremely quickly, any response plan demands a rapid reaction from all emergency response personnel."

The lahar early warning system alone was not enough and an integrated response including a warning system, warning system maintenance, education, research and response capacity was needed.

Once the Crater Lake had reached a predetermined level against the tephra dam of rock particles, police had to be in a position to respond within 20 minutes, Mr Ryan said.

It was anticipated that once the lake rose above the base of the tephra dam, it would take about 90 minutes for the lahar to reach the rail and road bridge at Tangiwai and even less time to get to the Desert Road.

- NZPA