In praise of scientists and engineers

[Parihaka]

On Christmas eve 1953 New Zealand suffered a major disaster when the crater lake of Mount Ruapehu burst it's banks a swept downhill, destroying a rail bridge at Tangiwai. Soon after a train plunged form the broken bridge into the lahar and killed 151 people.
After the recent eruption of Mount Ruapehu

it was feared that once the crater lake reformed that the same sort of disaster could occur again and much time was given to radio talkback and political mitherings about what should be done.
Popular consensus was that the crater wall should be bulldozed or blown open to allow the captive waters to escape but also much opposition due to the cultural sensitivity of the mountain.
Finally the light of reason shone forth with the GNS, the NZ governments science department saying that to blow the crater wall would be too dangerous for the personnel involved and that instead the mountain should simply be monitored instead, and that with proper communication between the department, DOC, and the local emergency services, there should be no danger to the public.
About three month ago I heard one of the GNS b0ffins confidently predict that the wall failure should occur mid-march, and so it proved to be.

Mt Ruapehu's crater lake has returned to its pre-1995 level after the dam holding back the acidic waters washed away yesterday and a lahar flowed down the mountainside.
The Department of Conservation (DOC) said the new level of the crater lake was 2529.4 metres above sea level, with the 40-metre breach in the dam washing down to hard rock.

DOC senior conservation officer Dave Wakelin said DOC staff had been up to the crater and the tephra dam – loosely compacted ash, scoria and pumice – had washed down to rock on the crater's rim.

"It's great news from our point of view,' he said.

"Now we have a crater lake back to what it was pre-1995. It's flowing down its natural outlet, rather than building up behind the dam."

The equipment monitoring activity in and around the crater still worked, he said.

"It never seemed to falter. It kept on working, exactly as we expected it to – exactly the way it was designed to work."

However, though the dam had burst and the danger posed by the lahar had passed, DOC and GNS Science staff would keep watching the mountain top, he said.

"Just because this has happened doesn't mean we have actually stopped work on anything. What will change now is the frequency of the monitoring."

"There's a lot of ongoing work – The more you can understand about the crater and the volcano, the better things are," Mr Wakelin said.

The sensors flashed out electronic messages at 10.47am as the seven-metre high soft rock and ash dam holding back the enormous crater lake began to crumble.

Yesterday the dam, created by Ruapehu's eruption in 1995 and stretching 85 metres along the crater rim, disintegrated and the pent-up acidic lake water gushed out.

The $5 million alarm system alerted emergency officials and triggered flashing lights and road barrier arms on the Desert Road section of State Highway 1 and on State Highway 49 near Tangiwai.

It was at Tangiwai on Christmas Eve 1953 that an enormous lahar roaring down from Ruapehu destroyed the rail bridge, plunging an express locomotive and carriages into the torrent with the loss of 151 lives.

Trains approaching Tangiwai yesterday ground to halt, warned about the danger.

The lahar was described by officials as "moderate" and did no damage to major bridges and roads, electricity pylons criss-crossing the volcanic plateau at the foot of Ruapehu, or property.

There were no reports of anyone caught by the lahar or injured in any way.

Meanwhile, National rail operator Ontrack has had to employ a security firm to prevent sightseers wandering on to the Tangiwai rail bridge.

Chief executive David George said it was ironic the sightseers were posing a greater danger to public safety than the lahar itself did.

"The Tangiwai rail bridge is etched in the memory of most New Zealanders because of the tragedy that unfolded there," Mr George said.

"But that's not a reason for people risking their lives by trespassing on the bridge to get a better look."

He slammed as "completely irresponsible" a teacher who tried to take a class of children on to the bridge this morning.

Not only did they prevent any loss of life or significant damage, but the new bridge, rebuilt after the 1953 disaster, survived intact, even though the flow this time was larger. Interestingly enough the memorial built above the tragedy site was swamped by the lahar.

cool.

[highsea]

The vulcanologists these days have pretty good ideas of what to expect. But I have to say, I'm very impressed by the mid-march prediction!

I was in college in Ellensburg, WA in 1980 when Mt St. Helens blew her top.

We were quite a distance (100 miles or so) removed, but it was surrealistic- night-time darkness at 10 a.m.; us kids wrapped wet bandannas around our faces and went racing around on our ten-speeds, churning up clouds of ash. It was a holiday, and the pubs sold out of everything on tap.

For everyone other than us kids, it was disruptive as hell; the cop cars had to jury-rigged big external air cleaners from Kenworth trucks because the ash was eating engines at an incredible rate, mud in the aisles of the local Albertsons and everything in the aisles was a uniform shade of gray. There were no brand names on that day, lol.

You could look at color pictures, and swear they were taken in black and white. We had 40' tall mounds of ash piled up along the I-90 all the way to Spokane and into Idaho; that's 150 miles, on both sides of the freeway! The DOT had no idea what to do with it. It's still there, though it's worn down by erosion over the years, and the sagebrush has covered most of it. Just another "feature" of the landscape now...

That was one of those days when you knew just exactly how small you really are. Kind of like a really good aurora borealis, or a full blown lunar eclipse combined with a really spectacular comet. Or lightning striking 30' from where you are standing. "Awe inspiring" doesn't really cover it.

I'm very relieved that the Mount Ruapehu eruption did not cause havoc. When I heard the news, I thought of you and yours, and I'm glad you checked in! I have a healthy respect for Mother Nature and her capacity to catch us offguard. She's done it before, and she'll do it again.

Glad to have you still with us, my friend. :)