[Reports Presented at 2001 FRFANZ Conference]
BARRY BRIDGES
INITIAL ATTACK ‑ Significant Fire, Boxing Day, 2000, Blenheim
Conditions
Barry Bridges, MarIborough DC PRFO, outlined
conditions prevailing before the outbreak of fire. There had been good spring
growth, but rainfall was much less than average in Nov/Dec. Temperatures were
higher than average. On the two days 25/26 Dec., these were 29% and even at
temperature was stable at around 24o in the north‑facing Withers
Hills. Relative humidity on the 26th
dropped to 40%, and the DC in the Awatere Valley was 581. All
firefighting resources were on alert.
Initial Attack 26
December
Barry is also Blenheim CFO. The first fire call of the morning was to
the Waihopai Valley, 35 km from Blenheim. While he was responding, a second
call was received at 1056 to Ward, about 60 km south of Blenheim. Barry
continued to Waihopai, and this fire was contained at about 20 ha. Blenheims
DCF0 responded to Ward, and helicopters were dispatched to assist there.
On returning from Waihopai, Barry heard the
calls to a fire on the Taylor Rd at 1601. He ordered a tanker to respond, and
got his first glimpse of smoke while still 12 km away when passing through
Renwick. On arrival, the fire was still on the flat, threatening houses on the
left flank. Appliances were sent in to deal with this flank, and the tanker
with spray boom sent in on the right to prevent the fire reaching the Wither
Hills, and a popular walking track. At this point, he had thought that it was
possible to cut the fire off. However, the fire spotted 100m ahead, and into
the hills, and was lost.
Fire Behaviour
Fire researcher Grant Pearce said
that the ISI in the Awatere Valley was 40.5 (47.9 at Woodbourne air field) on
the day. Grass on the Wither Hills was 95‑100% cured and the loading was
2.5‑7 t/ha. It was higher at Ward. There was therefore the potential for
head fire intensities of 18,500 kW/m, and a rate of spread of 10 kph on level
ground. At a 10o slope. the ROS would climb to 16.4 kph, and the
intensity to 41,000 kW/m.
Change of Tactics
With the Hills alight, Barry's immediate
concern was for trampers on the walkway, and the protection of property. There
was no information on how many may have been up there, although there were two
cars parked in the walkway carpark. He dispatched a 4WD up the hill to look,
and demanded two helicopters from the Ward fire. The first helicopter picked
two walkers off the hill, and a third managed to make his own way down. The
fire was making rapid progress in a NW direction to the State Highway. It
jumped and would ultimately be stopped by the sea. 100's of volunteers were
turning out, most dressed for the hot temperatures in shorts and singlets.
Refusal caused much criticism. Helicopters were ordered in from Wellington and,
in the heat of the moment, fixed‑wing aircraft were ignored although they
were readily available. Only the flanks of the fire could be worked on, and
contact with crews became very stretched. SAR arrived with a communications
vehicle, but this was incompatible. Aside from property protection (no houses
were lost), ground operations focused on heavy machinery to cut breaks. These
worked reasonably well, although the roll‑over was to cause lingering
problems. The head of the fire kept charging on, jumping roads. Helicopters
were stood down overnight, but bulldozers worked through.
