WILLOW FLAT CONTROL BURN

 

Report written by J.B. Everett for J.D. Rockell, Conservator of Forests

 

The debrief of the dramatic and fatal fire in Carter‑Holts Willow Flat Forest, held in Holts' office, Napier, on 1 April 1980, is a truthful and factual account of the event of 11 February 1980. There is no criticism of the debrief recordings, but it was subsequently considered that a narrative report of the fire would present easier reading.

 

Control Burn Plan No. 132‑04 was the third revised plan since 1978 and was contrived to clean an area of 172 ha of clearfelled and dessicated kanuka, up to 8 m tall, and scrub associates for planting P. radiata. The area lay over steep to precipitous country, 30 m cliffs were dominant features of the landscape, along the north flanks of Mohaka Forest and fell to the Mohaka River 340 m below. Close to this area in 1973 a non‑permit fire, lit by a neighbouring farmer's sons, fanned by west to north~west winds, swept into Mohaka Forest destroying 250 ha of young crops verging on the age of production thinning. Naturally, the officer‑in‑charge, Mr T. Pellett, had the protection of his forest uppermost in his mind when, in liaison with Carter-Holts field officers, he wrote the control burn plan as O/C of the burn.

 

It was paramount that any burning must take place in a wind 0‑5 blowing from a southerly direction over Mohaka forest and towards the deeply entrenched Mohaka River. So infrequent are southerly winds on good burning days in this area that the planners had to wait two years for burning conditions that met the prescription. Over what was an interminable period of waiting for the right weather, it was inevitable that unkind criticism from both sides became evident. O/C Pellett was determined his; forest would not be in jeopardy and Carter‑Holts' Officers were of an equally determined frame of mind that fire must consume the fuel so that their belated planting would not be left another year. The burn edge was about 300 m from Mohaka Forest.

 

So, with a forecast predicting winds from the prescribed quarter on the morning of 11 February, the command was issued to assemble on the steep flanks of the Mohaka Valley during early afternoon. The manpower of Mohaka Forest had been well trained and were seasoned at control burning; the forces of Carter‑Holts did not enjoy the same expertise and were more partisan in their approach to fire. Men were positioned where they would be of most use in containing fire jumps and break‑aways; Forest Service men to protect Mohaka Forest and Carter‑Holts’ men were spread out. down the fateful firebreak between the eastern edge of the burn area and their 1978 plantings, and on the west boundary.

 

Burning conditions were considered somewhat marginal. Mr Pellett was hopeful of a good burn, but both he and Carter‑Holts' man, Mr Kinita, were not of a buoyant frame of mind. Unsuitable weather had dogged this control burn for too long to raise a spirit of optimism. With the wind blowing steadily from the south at force 2‑3, and personnel arrayed to the best advantage, the helicopter owned by Helispray Ltd, equipped with AFID (one of their own manufacture), fire fighter, and piloted by Mr Alan Gordon, started the first burning run at 1455 hours. The initial runs were done in a zig‑zag fashion along the northern boundary of the burn area. Ranger Pellett used hand signals to direct the helicopter which was not equipped with radio. This arrangement, understood fully by the pilot and O/C of the fire, required Mr Pellett to move his position as the need arose so as to have an unhindered view of the light‑up.

The fire quickly built up in intensity and covered the rising hill slopes to a hill top near the southern boundary and about midway between east and west boundaries very quickly and at a speed not reckoned upon by the men around the perimeter. To contain the onrush of the fire in the gully immediately west and below the eastern firebreak, the helicopter was directed to diagonally light up from the northern end of the firebreak, across the steep face and head of the gully to Matai Road. A burn‑out strip would control and redirect the burning face of the main fire front away from the firebreak along the ridge where Carter‑Holts' nine men were standing to protect the 1978 planting on the east.

 

It was about this time, approximately 10 to 35 minutes before the stated time of the fire breakaway of 3.30 p.m. ‑ no witness has given a precise time to the event because of personal involvement and safety ‑ that the mass of fire had built up from the first helicopter burning run down near the Mohaka River and was entering a very steep sided and abruptly rising gully on the immediate west side of the eastern firebreak along which were standing Holts' men. The gully fanned out at Matai Road, but the middle section, or throat, was narrow and very steep, and was aptly called a "chimney" by one of Holts' men. No one person could give a time when the fire began its up‑hill rush through the "chimney", but an observant participant, who was not on the firebreak, stated it took the fire about 4˝  minutes to reach Matai Road, a distance of roughly 500 metres. This is an incredible velocity.

 

The devastating speed of the fire coming out of the "chimney" went through the retaining line of the back‑burn like a charge of cavalry through a single line of infantry, to Matai Road, across it and upwards to the top of the main range about 50 metres above the road and running at right angles to the lower subsidiary ridge which was the eastern flank of the burn area. During this spectacular display the nine men on the ridge remained steadfast, but over the crest from the heat and still prepared to deal with spot fires. When the mass of flame, burning debris and enormous super~heated updraught reached the top of the main range, it met the cool southerly wind of about force 3. Over the next minute and a half, circumstances of the fire rapidly changed, and it was during this brief span of time men and fire conditions created the drama that was to follow. Some of the events were patently obvious to the actors along the ridgetop firebreak, others can be reconstructed from experience of fire behaviour and some are were conjecture.

 

The steady, cool southerly wind forced the large cloud of smoke and airborne burning debris back over the fatal ridge and adjoining planted land of Holts. It was now that a vacuum, caused by the fire leaving the chimney, and the general area under flame, sucked in cool surrounding air. The scene was set for a moment of strange, if not terrifying, circumstances. Wind was drawn in from the east to north‑east beneath an enormous blanket of overhead smoke that was being blown north and simultaneously dropping burning debris on the nine men and planted area. This was inexplicably accompanied by a loud roaring sound that, along with smoke and flame and burning material, pervaded the area where the men were stationed. Spot fires had started to break out within the plantings east of where the firebreak met Matai Road, and with fire spanning their escape route down the ridge, the men suddenly realised the danger of their position. With the exception of Howard, Te Rito and Lawson, they dropped their tools and ran for Matai Road which the six gained in safety, though no doubt breathless.

 

The remaining three men being older and more experienced paused to sum up the situation which was worsening by the second. The planned avenues for retreat were hidden by dense smoke and incipient fires, and the burn area was still covered in flame. Howard, in these anxious seconds, observed a clear avenue through the smoke to the east, downhill through the young P. radiata to a gully and up the opposing face. He and his two companions took this route never realising the fearful hazards that awaited them beneath the tall grass.

 

In their reasoned and steady movement out of an unbearable situation wbich was not a headlong flight like that of the others, they struck headfirst the hidden snarl of fire‑scorched kanuka, within the planting, about midslope. This criss‑cross of charred sticks and poles lay about 2 ft to 2˝  ft deep and was hidden from them initially, and certainly from the planner and executors of the burn. In the words of Winston Howard, this was like a no‑mian's land of barbwire and took a great deal of clambering over. Meanwhile, the spot fires started by the burning debris were being fanned by the east to north‑east wind and had, by the time the three men reached the bottom of the slope, formed numerous blazing barriers that were as equally fierce as the main burn.

 

Howard reached the small stream and found a pool not big enough for his total immersion but sufficient for his body to be constantly splashed and made safe. He had the coolness of mind to keep a wet handkerchief in his mouth and over his nose. Thus he was to survive, and his injuries and debility were caused not by burning but radiated heat. At 5.40 p.m. Winston Howard was spotted from the helicopter, crawling on hands and knees up a burnt out ridge. So roughly between 3.45 p.m. and 4.30 p.m., when the breakaway fire had been brought under control, this man had fought for survival and won.

 

His not so fortunate companions did not reach the stream; their bodies were found up the slope by about 30 metres. It has been thought they may have sheltered in an area of short green manuka on a papa greasyback where they considered they were safe. Whether or not they were overcome by smoke at this point in their flight or they mistakenly believed they were safe, is conjecture. So much is not known about the behaviour of the fire in the chimney, the men on the ridgetop witnessed many aspects of it, but some facts may never be answered. What caused the roar is a mystery, what was the form of the smoke storm cloud above the main ridgetop conjures up many expressions of personal experience of fire, but none can he relied upon as observed and actual occurrences.

 

But, in all such disastrous happenings somewhere, someone has observed the event. In this case an interested member of the public had stopped his car on the Maungatananewha Road, well over a kilometre across the Mohaka River valley from the fire, and took a series of photos of the fire, particularly the conflagration of the "chimney". One coloured photo graphically shows a mass of flare a hundred feet high.

 

The eastern ridge of the burn area had the appearance of having been swept by a hurricane and small pumice particles up to pea size littered the qround like hailstones. A woman in Stowell's house 0.8 km north‑east of the burn (the former owner who lit the fire that burned Mohaka Forest in 1973) rushed outside to see the "hail" that was drumming on the roof. This was pumice. Holts' Foreman, Kinita, on Matai Road made a similar observation when he sheltered in his vehicle. The men on the ridge made what were considered exaggerated statements that whole trunks of kanuka up to 15 ft to 20 ft were carried upwards by the fire draught. The helicopter pilot who was too close for comfort and appeared to be surrounded by flying debris ‑ in all directions, is reported to have made the comment that he "got to hell out of here` very quickly.

 

Talk after such a dramatic event often gives little credence to actual happenings and truth is often stretched to suit people's imaginations. In the Mohaka crucible only those men positioned along the eastern ridge were aware of events. These participants in the drama, and from those who escaped lightly, and Winston Howard whose presence of mind preserved him from a ghastly fate, can give a true account of fire behaviour in those circumstances. Their opinions and observations have been corroborated by interested outsiders who, through casual remarks and photographing a spectacular fire, make statements from Holts' men less chimerical than otherwise have seemed.

 

It is not the purpose of this narrative to criticise the burn plan and its execution. It was approved in all its stages to Head Office, but suffice to add, the next burn done by Mohaka and Holts on similar country, up the valley, followed very different light‑up procedures. Some of the questions will never be answered, certain events were not witnessed, and will forever remain enigmas and subjects for much argument. Material burned with a far greater intensity than ever anticipated, and so swift and concentrated was the fire up the."chimney" that the removal of pumice from the B horizon of soil structure adds terrible testimony to the actual fire ferocity.

 

For men to have held their positions for so long is almost beyond belief. What caused the roar must be left to one's imagination: was it a twister of tornado force or some other phenomenon? No one knows for sure. This whole event from the tine the fire entered the "chimney", its express train speed upwards, the subsequent roar and drift northwards of the burning debris-filled cloud over the heads of the men took about 6 to 7 minutes. In such situations, that is little time for any force of men to take defensive or evasive action.

 

This narrative has been purposely long and over graphic as some staff will remark, but it has been the intention to report as faithfully as possible those actual happenings on the east ridge of the burn, and if readers can learn something from this report it will have served its purpose. Hawkes Bay District staff and Carter‑Holts will not forget; the experience has been a painful one.