Tongariro erupts - where will the ash cloud go?

WeatherWatch's Philip Duncan on where the ash is likely to fall.

GeoNet has confirmed that Mt Tongariro has again erupted this afternoon, sending an ash plume several hundred feet into the sky according to media reports.

WeatherWatch.co.nz has been checking the wind flows and wind speeds in the area.

Our feeling is that much of the ash will fall locally, due to only light winds in the region and therefore the ash will fall to the ground sooner.

However lighter ash can travel great distances at higher altitudes - and this can impact flight routes and airports.

The wind flow on the mountain and surrounding mountains/weather stations currently shows a light south westerly at ground level. Wind flows higher up are expected to be light also but generally pushing the ash in an easterly direction.

The plume may drift anywhere within the eastern quarter - anywhere from Taupo to Hawkes Bay at this early stage.

The forecast for the next five days shows light winds from the west, similar to today.

The good news, as like the last time Tongariro erupted, is that the wind flow is pushing any ash clouds away from the main North Island/South Island air route - which is to the west of the mountain (and the ash is being carried eastwards).
However it does mean ash will fall over State Highway 1, the Desert Road.

Strong smelling gases may travel much further, as it did last time. Those who are concerned are advised to check the GeoNet or GNS Science websites for full details.

Farmers and those who rely on rain water and are near the mountain - or in the potential path of ash - should disconnect rain water tanks immediately.

Motorists are reminded that while ash may seem fluffy, if it is in fact small and harsh rock particles - which scratches windscreens and can choke engines if thick enough.

- WeatherWatch.co.nz

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