OHINEWAIRUA FIRE REPORT

 

Report written by R.G. Armitage for J.D. Rockell Conservator of Forests

 

REQUIREMENT FOR REPORT

 

The fire that sprang from a controlled land clearing burn on Ohinewairua Station [in 1983], became a devastating wildfire that occupied large numbers of men, machines and organisations over an extended period of time. The fire size and impact has been such that many reports and recommendations have been made by individuals involved in the fire, but no one report detailed the whole sequence of events over time and each report or set of recommendations tended to relate to its author's or organisation's experience of the fire. Some reports were also required for a specific management purpose. The first, or narrative section of the report summarises what is known.

 

This report and its appended recommendations has attempted to utilise information available from fire logs, the two debriefs, and reports to record major events and summarise recommendations made to provide a sequential record. Formal reports from the other fire authorities present at the fire have not been received, although their officers participated actively in the first debrief and some comments from them have been recorded.

 

SEQUENCE OF RECORDED EVENTS

 

A major portion of this report is comprised of a collated list of sequentially (time) recorded events which together, combine to provide insights into various recorded incidents. [A map of the fire is available].

 

FIRE RISK OHINEWAIRUA STATION

 

There were no formal fire hazard readings taken on Ohinewairua or Ngamatea Stations prior to the fire, to record fire hazard. Speed of fire spread and fire intensity of the wildfire however clearly indicated that the hazard relative to fuel available was extreme. From fire start at 1500 hours Friday 4 February to 0630 hours Saturday 5 February the fire raced 12 km north, while from 0630 Saturday 5 February to 1800 hours Saturday 5 February it moved 19 km northeast. Severe fire intensity was indicated in many reports and Chief Soil Conservator I.H. Cairns reporting to Hawkes Bay Catchment Board noted, "destruction of all vegetation and in some cases removing of the duff layer to expose the pumice soil."

 

[daily FWI readings at Kaweka SF were 6th 76; 7th 110; 8th 74; 9th 23; 10th 26; 11th 5]

 

Hawkes Bay County Council whose western boundary lay close to the eastern fire flank, had recognised increased fire risk due to drought conditions and had imposed a restricted fire season. From 1 February 1983 they advertised that they had revoked the restricted fire season and had, from 1 February 1983 declared a prohibited fire season. Formal advice, or copies of the declaration under the Counties letterhead were sent to the Rangitikei County Council in a letter dated 31 January 1983.

 

FRIDAY 4 FEBRUARY

 

During the morning Ohinewairua Farm Manager D. Haines rang Rangitikei County Council Fire Officer G. Robertson to enquire as to the need for a permit to ignite scrub prepared for a land clearing burn. He was advised the County had no fire restrictions in force that required permit issue and he therefore determined to utilise a Wanganui Aero Works Helicopter piloted by J. Anderson, already scheduled that day to spray thistles on his property to light the prepared scrub from the air. He arranged for Anderson to light the fire when he had finished spraying the thistles.

 

Pilot Anderson began lighting the scrub at 1435. Manager Haines arrived at the fire 25 minutes later to view progress, in time to witness the fire jumping cleared ground to begin a fire in uncut standing scrub. Anderson radioed his base to alert them and call for two helicopters to be placed on standby, before flying to Taihape to pick up Roberston who was advised of the fire at 1545. By this time officers at Kaimanawa State Forest Park, Karioi State Forest and NZ Army Waiouru HQ had become aware of the smoke but were unable to locate the source. Karioi Forest and NZ Army Waiouru were advised of the fire by Robertson at 1600, while OC Kaimanawa D. Wilson was told the news at 1615. NZ Forest Service Wanganui District staff D. Cameron and Palmerston North Conservancy Officer J. Everett were also advised of the fire by 1615.

 

At 1625 Wanganui Aero Works had two helicopters fighting the fire and Robertson had assumed command of the fire. NZ Army Fire Master J. Blackburn, who had flown to the fire site with Robertson perceived the fire threat to the Army Defence Zone lands and at 1724 called for Army fire fighting teams to assist the County forces. Forest Service Napier District Ranger M. Benjamin was formally advised of the fire at 1940 and Head Office Senior Fire Control Officer N. Cooper received the news at 2235. At this time forces called to the fire included NZ Army Task Force and other units, Rangitikei County Council, Wanganui Aero Works, Taihape Fire Brigade and Winstone Afforestation Ltd crews, while fire crews within NZ Forest Services Western District had been placed on standby. The fire was thought to be spreading rapidly north and east along the western fire flank, with fire base on Ohinewairua Station. District Ranger Benjamin at 2330 ordered an officer from Kaweka SFP to drive to the fire and report back and also directed Officer in Charge Kaweka SFP W. Drayton to inspect the fire from the air at first light.

 

SATURDAY 5 FEBRUARY

 

Daylight revealed the fire had travelled some 12 km north to penetrate or come very close to Kaimanawa SFP. Although it was unrecognised at the time the fire had also penetrated the Military Reserve to the west. It had crossed the Rangitikei River. A gale force wind from west south west, force 7, gave promise of an almost impossible fire task.

 

Rangitikei County fire forces and their allies were all grouped on the western flanks of the fire at 0530 and a message was sent to the Forest Service advising no immediate assistance was required. OC Kaimanawa SFP Wilson and OC Kaweka SFP Drayton flew separate aircraft, over the fire scene from 0630 and their assessment of the fire and its potential  was relayed to Napier and Palmerston North. Assistant Conservator J. Everett in Palmerston North received this report from D/R Benjamin describing the fire's potential threat to Military Reserve (Defence Rural Fire District), Kaimanawa and Kaweka SFP's and Hawkes Bay County lands, and at 0700 issued the order for Drayton to assume command of the fire.

 

Drayton received this order while at Ngamatea Station at 0735 and having assumed the NZ Army were directing fire fighting, immediately rang Waiouru to advise of the decision. Major Rosevear accepted the direction and was asked to transfer his forces to Ngamatea Station with the exception of 50 men to remain to patrol the western flank. The total force comprised five helicopters, 150 men plus County, fire brigade and Winstone crews and equipment. Drayton was later advised these forces should reach Ngamatea Station by 1400 hours. Drayton later recorded that, at 0735, his fire control priorities were conditioned by:

 

(a)     The impossibility of a frontal attack given gale force winds and highly inflammable fuel.

 

(b)     The perceived fire threat to the exotic section of Kaweka SFP and a drought stricken Hawkes Bay.

 

He therefore determined that the major initial tasks were to mount flank attacks on the southern fire boundaries to prevent the fire racing east, through the tussock and scrub lands to Kuripapango and Hawkes Bay.

 

The first forestry fire forces began to arrive at Ngmatea Homestead, fire HQ for the fire duration, from 0900 and were directed to the south east fire flanks in the Tikitiki  Bush area. These crews plus other forces and equipment formed into a highly mobile task force. The combined force of helicopters to cool the fire intensity, bulldozers to crush remnant fire and clear a break, and men to consolidate the break and mop up, managed to race north east along the southern flank of the fast advancing fire from Tikitiki Bush to the Taruarau River, some 12 km between 0900 and 1300 hours to prevent the fire threat to the danger zones described.

 

During the afternoon the wind shifted to westerly force 5, gusting 6, and fire control priorities were able to be shifted to the north around Lake Horotea and to the south east fire flanks east of the Taruarau River. Some 40 Forest Service fire crew had joined the previously detailed fire forces. At 1920 hours the most serious fire threats were fires on the west bank of Manson Creek, around Lake Horotea and in the Pinnacles zone. OC Mohaka Forest F. Brewer assumed fire command overnight and was relieved by Drayton at 0600 Sunday.

 

SUNDAY 6 FEBRUARY

 

Winds had dropped to south west 2 by dawn and direct attacks on fire fronts became possible until wind strength increased in the afternoon. NZ Army forces were deployed on the northern and western flanks and NZ Forest Service crews attended the southern and eastern fire edges. By 0820 it was estimated that approximately 160 fire fighters were present, predominantly Army and Forest Service although volunteers from tramping clubs, Deerstalker Association and other groups were there and more arrived during the day. NZ Army assumed the demanding task of providing meals for the multitudes over the next two days. Early aerial patrols revealed the fire fronts were still west of Manson Creek and the Ngaruroro River and south of Stoney Creek. Early efforts were therefore made to hold these lines. Rangers Whiteside, Drayton, Brewer all took command at various times during this 24 hour period.

 

AT 1420 lowering humidities and increasing wind from the north west put great strain on all sectors to the extent that some advancing fires could not be attended to immediately and fire command had to place requests for action in priorities. The most serious containment effort was accorded to the south east flank from Taruarau River to Rocky Point to Mt Meany and the bulldozers there were recorded as having achieved 8 km of firebreak during the day. Drayton reported shortly after 1730 that the zones of most concern to him were at the Pinnacles in the north west, Rocky Point to Taruarau River in the south east and the eastern slopes of the Tawake Tohunga Range in the north, while fires were also recorded as active in the Otutu Bush area in the north east. Helicopter disposition at this time was recorded as, 9 on the northern fronts, 8 on southern flanks and one with OC Fire. Drayton left the fire scene as Fire boss at 2010 and was replaced by OC Mohaka F. Brewer.

 

MONDAY 7 FEBRUARY

 

Reports at 0820 indicated south west winds force 4 and light drizzle and that major activity areas were the zones adjacent to the Pinnacles and northern Taruarau River. Rangers Whiteside, Atkins and Brewer assumed fire command during the day. The most serious fire outbreaks occurred in the Pinnacles and along the south eastern flanks.

 

An operational review was undertaken at 1430 at Ngamatea HQ by senior Forest Service and NZ Army staff chaired by Conservator J. Rockell. The major decisions were to generally phase the scale of operations down in accord with fire conditions that prevailed at that time. The 15 helicopters present to be reduced to 6, Army forces including catering to leave the following morning, 68 forestry personnel to reduce to 40 and all volunteers to leave. A further conference was held at NZ Army HQ, Waiouru at 1630 attended by the most senior Forest Service and Army staff and matters of mutual concern were discussed.

 

When the fixed wing aerial patrol left the fire at 1935, the entire fire front was quiet bar smoke near the Golden Hills airstrip. Firemaster Blackburn reported to Ngamatea that evening, that NZ Armv men on the northern fire fronts that day, had extinguished 294 separate fires and that the APC carriers and the tracked carrier 548 holding 5,000 litres of water, had proved invaluable in the rolling open country.

 

TUESDAY 8 FEBRUARY

 

The reduced fire crews anticipated a day of mopping up by locating and extinguishing hot spots and heat sensitive cameras had been provided for this purpose. The wind however had become strong by mid morning, up to 20 knots and increased in strength from the north west from early afternoon to the point where the fixed wing aerial patrol by D. Wilson was forced back to Turangi. B. Atkins was OC Fire until 1600 when F. Brewer assumed command.

 

The fire force had been reduced to 3 helicopters, 3 bulldozers and 40 men. At 0835 fires had become active in the Pinnacles area and 2IC Kaweka M. Kupa was despatched with a small crew. Shortly after 0934 further crews were despatched to the Mt Meany zone to extinguish flareups. The fire control battle in the Pinnacles developed into a desperate affair as Kupa by 1325 had called for all available men, helicopters and bulldozers to prevent the fire exploding north through into the Batley Reserve and on into Kaimanawa SFP. Wind conditions were extremely turbulent.

 

Radio communication from Ngamatea HQ back to Kaweka HQ had failed during this period for the second time during the campaign. A second disaster occurred at this time in Taupo when the Lama helicopter crashed on take off while attempting to return to the fire in response to calls for assistance. By 1546 four helicopters were fighting fires in the Pinnacles. At this time many other hot spots had also become evident in the south east fire sectors. Fortunately for all, the wind dropped and changed after 1500 and by 1649 rain had fallen on the fires and allowed tired crews to return to Ngamatea at 1713.

 

WEDNESDAY 9 FEBRUARY

 

The early morning aerial patrol at 0725 reported fire activity in the northern, eastern and south east sectors as well as the Pinnacles, in spite of pools of surface water left from the overnight rain. W. Drayton had assumed fire command. Fire control forces had built up to 116 men again in response to the desperate situation of the previous day and six helicopters, four bulldozers were in use. At 0812 Minister of Forests Elworthy and Conservator of Forests Rockell visited Ngamatea HQ and were conducted on an aerial inspection of the fire zone. Fire commander Drayton recorded that this day, for the first time he felt the fire was under control as adequate forces were available throughout the day for each flare up as it was reported, and by 1630 he had advised that 40 men plus two helicopters would be adequate for anticipated mopping up work the following day

 

During the day problems in motivating fire crews were noted and were ascribed to lack of trained supervisors and lack of crew training in 'mop up' techniques.

 

10 FEBRUARY ‑ 27 MARCH

 

The incidence of fire outbreak decreased from this day on and the numbers of men and machines required daily, decreased accordingly. From Friday 11 on, the operation generally consisted of one helicopter, 10 men, intensive use of heat detection equipment and use of aerial patrols on afternoons when aerial turbulence prevented use of the heat detection camera. The ground crews were dispersed to hot spots as they were detected.

 

Other dates of note were:

 

14 February ‑ fire debrief Napier

17 February ‑ crews travelled daily to Ngamatea from this day on.

4 March ‑ daily patrolling and crew attendance ceased.

15 March ‑ fire formally declared out.

17 March ‑ second debrief Napier

27 March ‑ fire flared up again in Mt Meany zone, extinguished.

 

GENERAL COMMENT

 

Unusual and significant features of this campaign fire are related to the rapid fire spread over a great distance and the inaccessibility of the fire in terms of conventional wheeled transport. The NZ Army resources of Iroquois helicopters, tracked vehicles and the rapid availability of commercial helicopters, were essential for rapid transport of men and heavy equipment such as firetrol. It should be noted that the linear spread of fire was in excess of 30 km, while Ngamatea HQ was more than 7 km from the fire flanks. Just as the need to transport men and equipment quickly and often was a function of terrain and distance, so too was the need for extremely flexible communication nets for both short and long range radios. Problems were noted in forestry long range communication, ground to air communication, and a general shortage of portable radios for fire crews who sometimes had to be left with no means of communications.

 

An essential communication and reporting role was played by OC Kaimanawa SFP D. Wilson who overflew the fire, generally in extremely turbulent air conditions for very long periods from Saturday 5th on. His advice and ability to anticipate problem outbreaks were a significant contribution to fire control and co‑ordination over such a large area.

 

Lack of communication points, particularly during the first weekend of the fire created problems for the media, who had difficulty contacting senior officers due to telephone overload, i.e., only one telephone and it was tied up with fire management. The media resolved the problem by gathering information from anyone who would talk to them, resulting in much inaccurate information being broadcast. These inaccurate broadcasts plagued senior fire personnel for the fires first week.

 

The fire thrust two vastly differing systems of management close together for a prolonged period and that proximity exacerbated the differences in management systems, techniques and ethos. Both groups have management structures, equipment, resources and training which can be welded into an efficient campaign fire force and there is no doubt that the presence of both organisations in strength at this fire hastened control of the fire. An example of management differences noted was that NZ Army had Major Stubbs in command at Ngamatea HQ for the duration of Army presence, while NZ Forest Service had five senior officers alternating command on Sunday 6 and four again alternating on Monday 7 February.

 

The fact remains however that the fire was stopped and held!

 

All forces: fire authorities, volunteers, plant operators and aerial companies, pooled and combined their resources quickly and efficiently relative to conditions prevailing, to ' combat the threat the fire posed. The ability energy and initiative displayed by individuals, groups and organisations contributed much toward the speedy control of this fire.

 

[It was estimated that the burn area extended to 15,000 ha. It was a very remote fire, and probably holds the record for the largest number of helicopters used at any fire in NZ. Suppression costs totalled $1,000,000. ]