Sunday, March 15, 2015

The approaching storm

Cyclone Pam is headed for New Zealand this evening/tonight, and while it was deadly in the Pacific, it’s unlikely to be too bad once it reaches us. Even so, it’s a good reminder for New Zealanders to be prepared.

Cyclone Pam, which was a Category 5 cyclone, the most severe category, hit Pacific Island nations, devastating Vanuatu, where at least 8 are confirmed dead, though the actual number of fatalities is expected to be five or six times that. The cyclone is in a three-way tie for the strongest tropical cyclone ever recorded in the Southern Hemisphere.

The storm is now headed for New Zealand, which it should reach this evening or later tonight (there’s a site with live animated tracking, which is where the screenshot, above, is from), with the worst of it expected in the morning. Auckland is expected to have heavy rain and strong winds, but the eastern parts of the country are expected to get the worst of it, with storm surges and potential for 8 metre waves.

Despite the somewhat hysterical reporting by the New Zealand Herald, the actual impact of the storm on New Zealand is likely to be relatively minor. That has to do with our latitude as much as anything.

Tropical cyclones (also sometimes called depressions because of the low atmospheric pressure) are storm systems that form in the tropics where the oceans are warmest. They’re called “cyclones” because of their cyclonic winds. If the storms become intense enough, they’re called hurricanes in the Northern Hemisphere, while in the Southern Hemisphere they’re called cyclones, and in the northwest Pacific Ocean they’re called typhoons.

The cyclones in our region usually mostly affect the Pacific, which is why the death toll and damage may seem relatively low, compared with hurricanes that hit the USA. That’s because of lower population in the region, of course, as well as the less developed nature of many of the affected Pacific Islands. Those factors also mean that when a cyclone does hit them, it can be more devastating for them, relatively speaking, than a hurricane is for the USA.

When the cyclones start moving south, they start to weaken as the move over cooler water. By the time they reach New Zealand, they’re usually dramatically downgraded, sometimes being only a tropical storm. However, even a weakened storm can be deadly. In 1988, Cyclone Bola hit New Zealand, and even though it had been deeply downgraded by then, it nevertheless “created some of the heaviest rainfall totals for a single storm in the history of New Zealand, with some locations receiving more than half of their annual rainfall totals from the storm.” It killed three New Zealanders.

The fact that even greatly weakened cyclones can still be dangerous when they reach us means it was prudent for authorities to urge New Zealanders in the storm’s path to stock up so they have three days of food on hand—but we should all have that already, anyway, as part of our Get Ready, Get Thru preparations: Earthquakes and volcanoes are constant threats, after all. Storms like this one are just another threat.

Because cyclones rarely affect New Zealand as anything more than, maybe, a bad rainstorm, people become complacent. It’s the old, “because a thing has never happened, it never will happen” way of thinking. Still, if one is prepared for disaster as we should all be all the time, anyway, then that complacency might not be as risky as it otherwise might be. There’s no need for panic—just ordinary, run-of-the-mill, prudent precautions.

Making sure we all "Get Ready, Get Thru"—regardless of the threat—is always wise.

Some observations at our house (updated periodically): At 7:30 this morning, there was still some sunshine, through broken clouds, with the occasional gust of wind. By 9am, the skies had clouded over, though it was still bright. The winds were already picking up. By 10:30am, it was overcast like a normal rainy day, though with more constant winds, some of them quite gusty. By 11:30am, the clouds had thickened and the winds became somewhat stronger. The rains started around 3:30pm, spits and sprinkles at first, but full-on rain soon after. At 7:30pm, the rains and wind eased, which apparently happens when the wind switches direction. By 7:45pm it was back to how it had been for the previous few hours. Around 8:45pm, it was all quiet. Forecasts at 9pm were unchanged, with the worst for Auckland expected between midnight and 6am, and for East Cape and Gisborne probably after that. At about 9:45pm, Bella went outside, and when she came back a short time later, she was wet, but by no means soaked. Same for Sunny when she went outside around 10:20pm. It was still quiet. By midnight, the rain had returned and was steady and reasonably heavy, though there was little wind. I heard it for hours whenever I woke up, until 4am, when all was silent, and I thought the storm was over. But at around 7am when I got up, it was again raining steadily. By 9am, it was mere sprinkles and by 10am, the deck was already starting to dry out. And that concludes this particular list of observations at our house.


rogerogreen said...

good luck w that

Arthur Schenck (AmeriNZ) said...

So far, so… good?