Report gives insight into April storms

A recent paper presented to Bay of Plenty Regional Council provided some perspective on the size of the side-by-side storm events that struck the Bay of Plenty in April this year.

The report notes that, going into April, the Bay of Plenty region experienced a wet March with rainfall levels up to five times that of historical recorded monthly normal levels.

Soil moisture levels during March were higher than long term averages and had approached or exceeded soil saturation levels.

The first event, ex-Cyclone Debbie, was responsible for a large amount of rain across the entire region with record rainfall resulting in unprecedented lake/river levels and flows across the region.

Flood damage in Galatea caused by ex-cyclone Debbie. Photo/File

The recorded flood flows in the Whakatane River at the Valley Rd gauging site were 34 per cent higher than ever recorded before.

The Rangitaiki River flows reaching the Matahina Dam were 20 per cent higher than ever recorded before.

Around a week later, Cyclone Cook made landfall in the Bay of Plenty and subjected the region to high winds and high seas resulting in considerable damage.

During Cyclone Cook, the report shows a short but significant burst of extreme wind gusts and wave heights.

Slip on State Highway 30 near Whakamaru during Cyclone Cook. Photo/File

Bay of Plenty Regional Council's general manager integrated catchments Chris Ingle said the report provided an insight into the weather that had battered the region last month.

"Our data services team has a network of around 130 automated monitoring stations throughout the region and they collect a huge amount of valuable environmental data.

"This data provided invaluable insight during the events and again, now post-event, to help us understand how these events looked alongside long term trends and averages. It was a valuable to be able to provide this perspective to the council and wider public."

The most significant damage from ex-Cyclone Debbie was the breach of the stopbank at Edgecumbe causing wide-spread evacuations and damage to the township.

Both storms, in particular ex-Cyclone Debbie, are the backdrop to a number of planned reviews likely to be announced over the coming weeks as organisations and the public look for answers to questions arising from these events.