We’re expect­ing some severe winds overnight and in the morn­ing, and sens­ible people are bat­ten­ing down their meta­phor­ic­al (and occa­sion­ally lit­er­al) hatches. I saw a com­ment on a friend’s Face­book page from someone over­seas say­ing “but surely Wel­ling­ton houses are built for the wind?”, and the answer is yes, but gusts of 160km/h are extreme enough to cause dam­age even to build­ings designed for this brisk cli­mate. I inten­ded to link them to a map of build­ing code wind zones…only to find that (as far as I can see) there is no read­ily-avail­able over­view map. The WCC’s WebMap will let you bring up a wind zone lay­er and click on the zones, but it does­n’t give you the big pic­ture. So, I down­loaded the wind zone data from Koordin­ates, and quickly knocked this togeth­er.

WCC wind zones map
WCC wind zones map. Click for a much lar­ger ver­sion.

The zones are col­oured from least windy in yel­low through to win­di­est in red, with grey areas either out­side the WCC area or not built-up enough to war­rant mod­el­ling. The least windy areas, which are offi­cially “Medi­um Wind” rather than Low (because Wel­ling­ton, of course) are gen­er­ally where one would expect: rel­at­ively flat and sheltered basins such as John­son­ville, Khan­dal­lah-Ngaio, south­ern Te Aro to Ber­ham­pore, Kil­birnie and cent­ral Miramar.

As you’d expect, any­where hilly or on the water­front quickly goes into the High, Very High and jolly-sound­ing Extreme cat­egor­ies. These zones help build­ers and engin­eers apply NZS 3604 to help work out the bra­cing demand, thus ensur­ing your house does­n’t get turned into kind­ling every time there’s a little gale. Hope­fully. But Wel­ling­ton does­n’t stop there. The fiercest red zones on the map are cat­egor­ised as “Spe­cif­ic Design”, which is Build­ing Code-speak for “you’d be crazy to try to live here, but if you must, get an engin­eer to work out how to stop you from fly­ing away.” Unsur­pris­ingly, these excit­ing areas fol­low the major ridgelines, though there are some intriguing loc­al vari­ations (for instance, Hataitai’s ridge seems worse than the main Tangi-te-Keo ridge of Mt Vic­tor­ia).

I ima­gine that most of those who are blessed to live in the Spe­cial Design areas already know how to keep safe, and how their homes are affected dif­fer­ently in a north­erly (like right now) vs a south­erly (as in the 2013 storm). But this might help remind you to take extra care with clos­ing win­dows, lash­ing down pets, and secur­ing any garden fur­niture that has­n’t already relo­cated to the neigh­bour’s place.

[Photo by Per Bjørkum on Unsplash]