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Learning to live with natural disasters

In the Sea to Sky corridor there is a constant threat of landslides, floods and earthquakes. Are we doing enough to prevent a natural disaster?

In 2004 Pique investigated the status of natural disaster preparedness in the corridor. Eight years on, on the eve of the two-year anniversary of the devastating Mt. Meager slide near Pemberton, writer Dawn Green looks at the continuing challenges facing Sea to Sky municipalities, alongside significant wins for public safety.

It was raining so hard on the evening of Oct. 28, 1981 that Gina Boscariol — who was driving south to North Vancouver on Highway 99 — considered turning around.

"The leaves were blowing over the road, the power was out and you couldn't see in front of you. It was a spooky night," she recalls. Gina made it to the city that night unscathed, but her sister, Tami, 19, was not as fortunate. She was also on the highway that night, approximately half an hour after Gina.

Meanwhile, on the west flank of Brunswick Mountain at the 1,500-metre level, the heavy rain proved too much for an insignificant creek — super-saturated, its banks collapsed. Beginning as a mudslide, it sucked up mud and debris and hurtled down the mountainside at an alarming rate of 80 kilometres per hour, bearing straight for M Creek Bridge, three kilometres north of Lions Bay. The wooden trestle bridge didn't stand a chance against the wall of rapidly moving mud, six-metres high.

When the bridge collapsed, creating an 18-metre gap, it took a car and its passengers with it plunging down the face of the mountain. With the bridge gone a yawning maw remained and into its depth went other vehicles before the alarm was called around 12:30 a.m. In total, nine people died, including Tami and her boyfriend Wayne Short.

"The worst part was not knowing," says Gina, noting that it wasn't until Nov. 16, when Short's truck with two bodies inside was found in 80 metres of water in Howe Sound, just off the mouth of M Creek, that doubt was laid to rest for good

"It was disastrous — it couldn't have been any worse," says Tami's mom, Anne, 31 years on from that day. "We think of her every day."

Could more have been done to prevent this disaster?

Her father Willie thinks so.

He took part in the inquest into the tragedy — one of the worst disasters in B.C.'s highway history. With his extensive logging experience, Willie helped assess the cause of the slide. He and three other loggers were flown up the mountain and he couldn't believe what they saw.

"It was just a mess up there, with stumps and debris in the creek," he recalled, adding that when the logging occurred there was no highway below.

"They should have done something before they built a highway. They should have had a look up there because it was a disaster waiting to happen."

The Sea to Sky Highway – a lifeline at risk

The Sea to Sky corridor stretches 110 kilometres from Horseshoe Bay to Pemberton, B.C. Historically, the corridor has been vulnerable to natural hazards of all sorts. More than 18 per cent of Canada's total landslide-related deaths have occurred along this route and over the last 150 years hundreds of landslide events have been reported.

It is the mandate of the Geological Survey of Canada (GSC), part of Natural Resources Canada, to decrease losses from natural hazards and to enhance disaster response preparedness. Research scientist Andree Blais-Stevens has written numerous publications on the natural hazards of the region, including a paper written with Oldrich Hungr in 2008, Landslide Hazards and their Mitigation along the Sea to Sky Corridor.

In the report, Blais-Stevens describes the Sea to Sky Highway as a major transportation and energy lifeline, which is at high risk.

Their research revealed the observed trend in landslide frequency having a peak period during the 1980s and 1990s at approximately 40 events per decade. In recent decades, the observed trend indicates the positive effects of improved slope maintenance and landslide mitigation measures.

If you were to make up a hit list of the top natural hazards in the corridor, Porteau Bluffs would most certainly be up near the top.

The area has experienced at least four major rockslides since the highway opened in 1958. Two of those, in 1969 and 1991, resulted in fatalities.

And then in 2008 another massive rock slide occurred. The highway was closed on July 29 at 11:30 p.m. when a rock slide deposited up to 16,000 cubic metres of debris onto both lanes of the highway. One vehicle was damaged in the slide. The highway re-opened on Aug. 2 to all traffic.

Squamish-based Geological engineer Frank Bauman calls the area "troubling for the potential of future rock falls."

He describes Porteau Bluffs as a leaning stack of books. And if you take the toe out of the first book, of course everything else is going to come down.

"The problem is that there are all these slabs of rock that are down sloping, pointing towards the highway," he said, "and they will occasionally release. They have spent a lot of time bolting it together but bolting is not a 100 per cent sure thing."

Bauman says what's really needed at Porteau Bluffs is a tunnel through the hazardous zone, which was the original recommendation by the design engineers for the highway.

"I have a couple of friends that are geotechnical engineers from Switzerland who have looked at it and shaken their heads and said that if this was in Switzerland, it would be totally unacceptable ... there they are much more proactive in terms of tunnelling, despite the cost, when they have a hazard like that."

A statement issued by Kate Trotter, public affairs officer of the Ministry of Transportation and Infrastructure, said that a tunnel was considered as part of the highway improvements.

"There were significant construction challenges identified, as the rock at that location is not conducive to tunnelling, and there also would have been impacts to the adjacent community.

The cost would have been in the range of $200 million — a third of the total budget of the Sea-to-Sky Highway Improvement Project."

Learning from the past

By understanding what has happened in past natural disasters, planners can prepare for the future, explains Bauman.

There are many lessons to draw from.

Britannia remains the site of one of B.C.'s worst natural disasters. On March 22, 1915 a landslide took the lives of 56 men, women and children who were living in a makeshift mining camp at the bottom of a steep slope.

The mining company, shocked by what happened, moved the residences down onto the flat land at the bottom of the slope.

But disaster struck again six years later when a blocked culvert above the camp caused the creek to burst its confines, sending a torrent of water toward the town and killing 37 people.

Squamish was also affected by flooding triggered by a stormfront pounding the area at the same time.

Flooding is certainly not a new concept to the town.

Most recently, hundreds of residents of Squamish and Pemberton were evacuated in October 2003 when the worst floods in over a decade took their toll.

The unstable slope of Mount Garibaldi which looms above the town has also experienced recurrent landslides, producing a huge debris fan at the mouth of the Cheekeye River just north of Brackendale. The possibility of a large landslide places limits on how far the community can expand into the fan.

Local conservationist John Buchanan, a long-time Squamish resident, recalls stories of the Cheekeye River blocking up, "and you can tell you are in trouble when the water stops running... it's quite scary for the locals."

Bauman conducted one of the very first studies on the Cheekeye Fan and says, "The bottomline right now is that there are... many studies that established the certainty that debris flows are likely to occur. What is interesting about the Cheekeye Fan is that after the Mt. Meager slide, it's really caused a major re-think about whether we are being conservative enough on the Cheekeye Fan."

In the early hours of Friday, Aug. 6, 2010, north-west of Pemberton, an enormous rock and debris landslide of about 50 million cubic metres in size swept from Mt. Meager (a potentially active volcano) through Capricorn Creek, then flowed into and dammed Meager Creek and partially blocked the Lillooet River.

For Pemberton Search and Rescue (SAR) manager Dave Steers that day is firmly etched in his mind.

It started with an early morning wake-up call after the alarm was raised by a worker at a pumice mine near Mt. Meager. A truck driver encountered a road blocked by debris.

At that point no one knew the size of the slide and nothing prepared him for what he was about to see, says Steers.

He, along with the other SAR manager Russell McNolty and pilot Steve Gray flew up in a helicopter to find out what had happened.

The first thing they noticed was that the level of the Lillooet River had dropped — they could see the gravel bars were wet but there was no water there any longer.

"So the level of the river was going down, not up – not a good sign," he said.

"We came around the final corner where you finally get to see what happened and nobody said anything... until Steve Gray finally said, 'Biblical,' which was quite an apt comment, I thought."

The size of the slide was "truly astonishing," recalls Steers. A third of Mt. Meager fell into the valley and chunks of icethe size of pickup trucks lay scattered on the valley bottom, a vivid reminder of the incredible forces at work.

Because the BC Ministry of Forests was using a hazard management plan that required closing the area during periods of hot weather when maximum snow and glacier melt would occur, the valley was closed at the time of the slide, thus preventing deaths in the area.

It was the second largest landslide recorded in Canadian history.

Bauman had conducted a major study of the volcano but the event was 10 times larger than he had predicted it to be, "so we need to recognize that despite our best efforts, there's a measure of uncertainty and we have to err on the side of caution."

This is where the district of Squamish (DOS) has done a good job, he continued. Despite pressure from developers, the DOS has not allowed development in the most vulnerable parts of the Cheekeye Fan.

Long-term planning must also take into account how an earthquake — and we are overdue for a big one — would affect the corridor and what would happen if one of the region's three volcanoes erupted.

Flood concerns

For Ryan Wainwright, Squamish Lillooet Regional District (SLRD) emergency program manager, spring is flooding time in the Pemberton Valley.

Annual flooding on the Birkenhead River rallies local authorities into action, taking on sandbagging in the community of Mount Currie, along with other flood protection measures.

Wainwright says that the situation has become worse over the past few years because the course of the river is changing, pushing more water back into the Grandmother Slough, which tends to collect debris.

"So its carrying capacity right now is probably not what it should be," he said from his office in Pemberton, adding that clearing work is planned for that water system later this summer.

Wainwright blames the continuous precipitation for the flooding, noting it is not so much the amount of snow that is up there, it is how fast it comes down. The river gauges indicate the Birkenhead River can rise more than 50 centimetres in 24 hours.

"The situation we are dealing with is really a protracted one in that there is a lot of snow up there in the Tenquille reservoir and that is where the Birkenhead drains from — there is about 132 per cent of the normal snowpack for an average year."

He points out that the local jurisdictions — the SLRD, the Village of Pemberton, Lillooet-Mt. Currie and the Pemberton Valley Dyking District — have been petitioning the province to install a warning system on the river, but thus far they have not been successful in obtaining the necessary funding.

According to Wainwright, the best solution at this point for a warning system would be a water gauge on the forestry bridge in the Upper Meadows with a bit of a technical add-on.

"So essentially if the river level dropped or rose precipitously, it would notify us by email or cell phone to alert us and we could send someone up to investigate," he said.

With a price tag of $20,000 for the warning system, Wainwright admits it's frustrating that the money has not been forthcoming from either the federal or provincial government to date.

"It seems like a very cheap and easy fix, but any time you try to strike cooperation between the federal, provincial and a local government on an issue, there are always complications in terms of whose responsibility it actually is, and what budget year it fits in."

Downloading danger

As we have seen, any natural disaster preventative measurements require funding, a responsibility which provincial government authorities have been quick to place directly on municipal hands, with the downloading of costs.

At the July 3 meeting of the Whistler municipal council, following a presentation on the municipality's Hazard, Risk and Vulnerability Assessment (HRVA) — an assessment mandated by the provincial government — Whistler Mayor Nancy Wilhelm-Morden called it a classic case of downloading.

Hazard assessments were once the work of the province, but are now conducted by communities via a HRVA toolkit.

The assessment identified 32 hazards in Whistler, five with a high rating. These include earthquake, snowstorm, interface fire, volcano and interruption to water supply.

The mayor asked staff if Whistler gets any funding for training for emergency preparedness, to which the response was that this was the last year for federal funding, while the province provides funds for some training.

In May this year, the BC Mayors' Caucus met in Penticton and discussed forming a new relationship between the provincial and municipal levels of government.

Whistler Mayor Nancy Wilhelm-Morden attended the meeting. She said the purpose was to look at what they are calling "mandate creep."

"The provincial and federal governments are both downloading their responsibilities to the municipalities as a way of managing their budget deficits, and of course no municipality can run deficits and we have limited revenue sources."

She expressed her concerns around funding.

"In addition to property taxes that we raise on our own, we receive grants from other levels of government – but the problem with grants is that they are entirely unpredictable, there's no certainty from year to year. The municipalities find that they are competing against one another for these grants from senior levels of government and it's a very unsatisfactory way to try to plan, from a fiscal perspective, so we want to see the end of the grants scheme and something that has more certainty."

Wilhelm-Morden said resolutions to the issue of downloading were drafted at the BC Mayors Caucus and that a task force was charged with going back to the province and starting meaningful discussions on creating new relationships.

The task force will deliver a report when the Mayors Caucus meets again at the end of September, just ahead of the Union of British Columbia Municipalities (UBCM) conference.

UBCM president Heath Slee gave the UBCM's take on government downloading.

"One of the issues that unites local government leaders around the province is the impact of downloading on communities," he said.

"There is a way to remedy these challenges though, and that is by having all levels of government meet to make sure that the revenue tools available to local government are adequate for the services we are providing. That was one of the promises on the premier's agenda and it is a conversation that we will need to have."

Mitigation measures

The Sea to Sky corridor is known as an area with a high potential for landslide occurrences and it is in an area that is increasing in population and tourism, says research scientist Blais-Stevens.    

The major findings of the study she did along with Oldrich Hungr's study indicate that there have been more than 150 landslide events since the first historical account in 1855-56. These are more abundant in the southern part of the corridor from Porteau Cove to Horseshoe Bay than in the northern part.  The southern part is also the area where infrastructure is built close to steep slopes. 

She points out the next steps to follow.

"Now that a regional assessment has been conducted, more detailed work could be carried out on specific landslide sites to better understand trigger mechanisms," she said. 

According to Blais-Steven's research, certain landslide disasters led to the implementation of mitigation measures. Active protection structures have been constructed and road safety measures introduced. In addition to this, systematic mitigation of rock falls and the adoption of the Rockfall Hazard Rating System were implemented by the B.C. Ministry of Transportation and Highways.

Blais-Stevens says these evolving mitigative measures since the 1970s have increased the safety of the population, with no reported fatal accidents caused by landslides in the corridor since the early 1990s –although luck has also played a part in that.

Where to from here?

With increasing population density in the corridor, more attention needs to be paid to the potential for high-magnitude low-frequency landslide hazards, states Blais-Stevens in her report.

The Barrier in the Garibaldi area is a good example of how the history of a major hazard shapes policy on land use.

We know from scientific and geotechnical work that the last big landslide off the Barrier down Rubble Creek occurred in 1856-57.

It sent 25 million cubic metres of material hurtling down the creek. That's enough debris to bury the town of Whistler.

Another slide could impact Daisy Lake Dam and send gravel and sand downstream in the Cheakamus River, which could cause the water levels to rise and threaten Squamish, explained Bauman.

For this reason in 1980 the provincial government designated the Rubble Creek area along Highway 99 as being too hazardous for human habitation and spent $17 million to buy out property owners in the former settlement of Garibaldi.

"With the Barrier there's no doubt there will be another event but they only happen every few thousand years," Bauman said.

"That's the problem with these studies, we're dealing with long time periods, but we're dealing with pretty significant potential consequences both if we're right and if we're wrong. So that's the trick with these things, these assessments can't be too conservative but they can't, on the other hand, overstate hazards either which then inhibits development and causes all sorts of unnecessary panic."

He added that it's problematic as they really don't want to put houses into areas where there's even the slightest chance of landslides.

Rubble Creek drains out of the valley and Bauman says the issue there is that if the big apron of loose rock at the base of the Barrier gets saturated with water, it could release and flow down the valley and hit Highway 99 along with the water in Garibaldi Lake.

Studies declared it dangerous but despite the recommendations, the Ministry of Transportation and Highways didn't move the highway to the west side of the river.

"They moved residents of Garibaldi claiming it was a horrible hazard but all the motorists who travel Highway 99 still have to travel through that same zone," Bauman said.

Bauman's concern has been echoed by a Whistler resident whose letter to the editor appeared in Pique in May.

Rupert Merer was held up on Highway 99 on May 20 by a head-on collision vehicle accident close to the Daisy Lake Dam.

"Trapping several thousand people for about two to three hours in the middle of a high risk slide area is not smart," he wrote. "Those who are responsible for traffic management after an accident should consider all of the factors — relative traffic flows and slide risk. If there had been a moderate quake on Saturday, followed by a slide, we would have experienced a Titanic-sized disaster."

Yet Bauman believes that we've come a long way in terms of risk management.

To assist cash-strapped municipalities in developing appropriate natural hazard management programs, the Association of BC Professional Engineers and Geoscientists (of which Bauman is a member) released a set of guidelines entitled Guidelines for Legislated Landslide Assessment for Proposed Residential Developments in BC in May 2010. It will also help districts in reviewing development applications, said Bauman.

"So there is, in fact, a greater recognition," he said, adding the hazards policy was a huge step in the right direction because it sets the standard by which all engineers and geoscientists are expected to live up to.

As for lessons learned from the past and looking at future developments in the corridor, Bauman says he thinks the critical point is that the reason that these hazards happen is because we are in mountainous terrain.

"We're close to a plate boundary where the collision of Juan de Fuca plate and the North America plate have pushed up these mountains and basically what goes up must eventually come down when there's enough rain, ice and snow. And we will never stop these natural hazards from occurring, they are part of the landscape. But where we have the control as human beings is to have policies in place to recognize these natural hazards and deal with them."

He points to the need for municipalities to have bylaws that ensure that if people live on floodplains, for example, that they adequately protect themselves.

"So I always say they are natural hazards, they won't go away but they are predictable for the most part and preventable. Sometimes we fail to react to the warnings that Mother Nature gives."

He notes that the research done by scientists such as Blais-Stevens is especially important nowadays with the climate warming up.

"We seem to be going through some unusual climate changes in the sense of more rain and so forth and those are the things that can create problems. Climate warming is expected to cause sea levels to rise and therefore we need to be more careful when we allow developments close to sea level, for example in the Squamish area.

"The mark of a civilised society is that it takes a long-term view and it makes sure that these natural hazards don't become disasters," he said. "And we have it very much in our control to help ensure that that doesn't happen."

Natural hazard hotspots in the Sea to Sky corridor

The current number one concern, according to geological engineer Frank Bauman, is the Fountain Valley slide, situated 10 kilometres past Lillooet. He says it is a worrisome failure because it is actively moving and it threatens to undermine both Highway 99 and the CN railway tracks.

Another major hazard is located at Britannia Creek Basin and Jane Basin. A massive failure of 20 million cubic metres of rock detached up high in the mountains and is slowly moving down into the valley. Preliminary observations by several specialists, including Oldrich Hungr, indicate that the heavily fractured volcaniclastic bedrock could fail catastrophically. However, more detailed research and monitoring are needed to confirm the hazard. If there is potential for slope failure, Britannia Beach and the Sea to Sky Highway could be at risk.

Of special concern to research scientists such as Andree Blais-Stevens are high-magnitude, low-frequency landslides at locations such as Jane Creek, the Cheekeye Fan and Rubble Creek.

Appropriate management of these risks represents an important challenge for the geoscience and engineering professions in the region, she said.

Good news scenarios

The community of Lions Bay is no stranger to natural disasters. The source stems from a number of creeks that experienced major debris flows, which swept down with tragic consequences in the 1980s. One killed the two sons of the then-mayor, another claimed nine lives when M Creek Bridge was washed away and a debris flow also took the life of a pregnant woman.

As a result of these tragedies, the Ministry of Transportation and Highways and the province built three catchment basins to control extreme stream discharge debris flows.

"When they were installed in the 1980s, they were very expensive," said geological engineer Frank Bauman, "but there hasn't been any problems since. They're an example of how we need to go about dealing with natural hazards."

Another example of natural disaster prevention at work is the Fitzsimmons Creek debris barrier in Whistler, which was completed in 2009.

The debris barrier is a large steel grill approximately eight metres tall and 12 metres wide that spans Fitzsimmons Creek, two and a half kilometres above the village. It is anchored with concrete and reinforced earth abutments on either side of the creek. In the event of a flood, the barrier will prevent debris, including large quantities of sediment, rocks, and logs from blocking Fitzsimmons Creek.

Bauman says it was a major step to build a catchment on Fitzsimmons Creek as it has effectively removed the very real threat to the parking lots next to the village.

Another debris barrier was installed on Whistler Creek when Intrawest redeveloped Creekside.