Why was the storm so severe?

[tich]

I'm talking about the big one that dumped on the lower NI on Sunday and Monday. My guess is that it wasn't only because the weather system was extremely intense, but also due to the ground already being saturated by heavy rain not long before. I recall there was a 2 or 3 day period of heavy rain in the southwest of the North Island a few days earlier.

The media stressed the worst affected areas as being from South Taranaki down to Horowhenua. The system responsible was a deep low to the east, with a very strong southerly on its western flank. You'd think that normally the Wairarapa and Hawkes Bay would suffer more flooding damage in such a situation. While those areas certainly got a bad hiding, they weren't in the news nearly as much as the Manawutu and Wanganui areas. The southeast of the North Island obviously wasn't already saturated from the earlier rain.

It's been said that this last storm was the worst NZ disaster in $ terms since the Napier Eathquake. However, I can't believe it was worse in meteorogical terms than Cyclone Bola. But then again Bola ravaged less heavily populated areas. It must also be stressed the the continuing bad weather following the big storm has additionally contributed to the scale of the devastation. BTW if such a storm had hit somewhere say in Indonesia or India, the damage would be measured in terms of the number of human lives lost. We're lucky in NZ that while it was devastating to property and livelihoods, there hasn't been any loss of human life directly attributed tot he storm that I've heard about.

[Willoughby]

I agree. You said it all.

[Michael]

Those areas get gales from the SE down there and after lots of westerly rain it doesnt help

The media stressed the worst affected areas as being from South Taranaki down to Horowhenua. The system responsible was a deep low to the east, with a very strong southerly on its western flank. You'd think that normally the Wairarapa and Hawkes Bay would suffer more flooding damage in such a situation. While those areas certainly got a bad hiding, they weren't in the news nearly as much as the Manawutu and Wanganui areas. The southeast of the North Island obviously wasn't already saturated from the earlier rain.

[spwill]

I think the geography of that area contributed to the Storm damage as well i.e. the bottom of a steep Valley is not a good place to be when 200mm of rain come down .

[Manukau heads obs]

it was the wrap around nature of the rain bands, i.e they got the east and west of the ranges in one hit!
and becuase it was so widespread rain
add that to the above too