Friday, February 5, 2016

Avalanche fortune-telling, aka how we decide when to close passes for prevention work

Barbara LaBoe

How are you at predicting the future?

Avalanche Control Specialist John Stimberis checks weather
forecasts and computer models regularly to measure avalanche risk.
That’s the ultimate job description of our Avalanche Control crews, who work throughout the winter and early spring keeping our passes clear and the traveling public safe.

They’re tasked with both anticipating and preventing natural avalanches that could cover highways and bury vehicles.  They don’t peer into crystal balls, but they do use a variety of tools – including explosives –  to keep one step ahead of the snow.

By definition, avalanche control work means closing passes while snow slides are triggered and then the roadway is cleared. We know that’s disruptive to travelers and, when possible, we schedule the work for non-peak hours. Sometimes, though, conditions and the safety of motorists and our crews working the passes don’t allow for delays.

So, how do we decide when to conduct avalanche control work?

The short answer is whenever we feel the risk of a natural avalanche on the roadway is too high.

Stimberis uses a bucket to sample snow, measuring the water
content to determine the density of the snowpack.
The longer answer is that it’s a complicated alchemy of science, weather forecasts, historical data, traffic volumes, maintenance equipment availability and just general “snow sense” that our highly skilled crews calculate every day.

Our avalanche crews start with the science, including detailed weather forecasts, computer models and historical slide information. Snow pack information, temperatures, wind speed, wind direction precipitation and snow levels are all tracked to see which – if any – are increasing that day’s avalanche risk.

Next, they move on to the snow.

Snow consistency is studied and measured for water content and density. The snow’s temperature is taken and large blocks of snow are examined for any evidence of shears – or weak spots within the snow pack that could break loose and act as a sliding layer to bring snow down the mountain.

The final step is that little something extra that comes with experience – a sort of fortune telling for the snow. Using the models, data and a healthy dose of their own knowledge of the particular area, crews determine what the snow is expected to do in next 12 hours. Our crews are often ski patrol veterans, which can be valuable experience when it comes to evaluating snowpack and predicting next moves.

Stimberis shears off blocks of snow while measuring
a snowpack’s stability.
At times, some of their conclusions may seem counterintuitive to motorists. It doesn’t have to be snowing, for example, for the avalanche risk to increase. Roads may look bare and wet, but heavy rainfall puts extra weight on the snowpack that can trigger an avalanche. Warming temperatures – or even several hours of sun during a clear day – can also increase avalanche risks even during seemingly “perfect” pass driving conditions.

Can we prevent every avalanche? No. Nothing involving Mother Nature is ever 100 percent controllable.

But forecasting avalanche danger helps reduce the risk to motorists and our maintenance crews as well as decreasing the amount of snow available if a natural slide was to occur.

And, even though they can be frustrating, that’s the goal of every avalanche control closure: Reducing risks and keeping motorists safe.

Good news for SR 99 commuters: first phase of lane closures wrapping up early


By Chelsey Funis   
Last week we reported that crews were making good progress as they worked to install sign foundations on SR 99/Aurora Avenue North in Seattle. Turns out good progress leads to good news: the first phase of sign foundation work is finishing ahead of schedule. By Friday afternoon, median lane closures should be removed and the southbound bus-only lane will be restored to normal operations.
It may be tough to tell, but the new foundations for each sign on SR 99 extend 14 to 18 feet below the
roadway surface in order to hold a 7,000 pound steel cantilever structure and a new sign.
Sign foundation work isn’t done just yet, though. Beginning Monday, Feb. 8, crews will begin the second and final phase of this effort. They’ll be drilling, placing rebar and pouring concrete for one remaining sign foundation near Comstock Street. This phase is expected to be complete within 2 to 3 weeks and isn’t expected to significantly impact traffic, transit or pedestrians traveling on Aurora. 

Traffic details for the next phase of work include: 

  • The southbound curb/bus-only lane will be closed near Comstock Street for approximately one block.
  • An additional southbound lane may close overnight. 
  • Buses traveling in the bus-only lane will merge into the general purpose lane a few blocks north of where the bus-only lane currently ends.
Minor electrical work: Feb. 8 through early March
As foundation work near Comstock Street progresses, electrical crews will be installing underground electrical cabinets at the sign foundations, wiring for a new traffic camera and connecting communications lines to the existing overhead system. Electrical work is expected to take 4 to 5 weeks to complete and will require an intermittent, localized lane closure at specific points along southbound SR 99. These closures will be limited to off-peak hours only (10 a.m. to 2 p.m.).

Although traffic and travel times are expected to remain fairly normal for the next few weeks, we appreciate your continued patience, flexibility and attentiveness as you travel on Aurora. If you would like additional information about the lane closures or ongoing construction at the north end of the SR 99 tunnel, please visit our project website.

Wednesday, February 3, 2016

Why does it seem Snoqualmie Pass is closing more this winter?

By Meagan Lott

Let’s be honest, last winter felt more like an extension of summer. We didn’t close Snoqualmie Pass once for avalanche control work. It barely received 80 inches of snow. So driving over the pass didn’t really require the need to check if it would be closed.

The weather took a drastic turn this winter. December 2015 was a whopper of a month dumping a total of 200 inches of snow, with 112 of those inches falling the last week of December, breaking the historical snowfall record for a 7-day period.  To date, Snoqualmie Pass has received over 300 inches of snow while the 30-year average is about 233 inches for this time of year. This has led to several extended closures for snow removal and avalanche danger. In addition to the weather related closures, two separate collisions involving fuel trucks required day-long closures to safely clean-up the flammable material.

Crews cleaning up after avalanche control work by the new avalanche bridge

The construction project to expand I-90 from four to six lanes is also causing more closures this winter. When the snowshed was removed in 2014, we knew it would take two winters before the first of two new avalanche bridges were finished and would require more closures for avalanche control work. It also meant putting traffic closer to the hillside reducing the space we had to store snow.

This summer, crews will shift traffic onto the new eastbound avalanche bridge, so by next winter there should be fewer closures from avalanche control work because our most active avalanche paths along Keechelus Lake will no longer deposit snow onto the highway. By 2018, the westbound avalanche bridge will be finished and both bridges will take drivers up an over a series of avalanche paths that will allow snow, rock and other avalanche debris to go under the bridge piers. Although the new avalanche bridges and other improvements on I-90 will reduce closures in the winter, there will still be the need to close the pass due to collisions and stalled vehicles as well as some avalanche control work west of the Snoqualmie Pass Summit.

The new eastbound avalanche bridge this winter

Our team of managers and staff on Snoqualmie Pass are well trained with decades of experience. They handle a wide range of duties involving snow and ice removal, responding to collisions and reducing the danger of avalanches. During a snow event, there can be up to 30 pieces of snow removal equipment including plows, graders and blowers on I-90 from Vantage to North Bend. Snow plows push the snow off the highway in tandem from one blade to the next efficiently moving it off the highway. If you don’t see snowplows in bad weather, chances are, they are behind you.

Our equipment technicians are on-call 24/7 and work tirelessly to keep all the equipment working on the highway in good repair. We coordinate closely with the Washington State Patrol on traction requirements and closures for unsafe conditions.  Our Traffic Management Center staff are in constant contact with crews in the field and monitor cameras, update the website, the highway advisory radio and variable message signs to keep drivers informed on current conditions.

We understand I-90 over Snoqualmie Pass is a vital transportation corridor for our state's economy. Our goal is to efficiently move people and goods across the pass, but our number one priority is safety.

Thursday, January 28, 2016

Sign foundation work progressing well on SR 99 in Seattle

By Chelsey Funis

Crews used a large drill to dig several 4½-foot wide,
14-to-18-foot-deep holes for new sign foundations on
SR 99 in Seattle.
If you're a regular user of SR 99/Aurora Avenue North between the Aurora Bridge and just north of Mercer Street, we'd like to thank you for doing your part to help keep traffic delays to a minimum during the past two weeks.

Crews are around the halfway mark for the first phase of sign foundation installation work happening on this stretch of SR 99 and are pleased with the progress they've made. Work is continuing on schedule and crews expect to move into the second phase in mid-February as planned.

We've been trying to do our part, too, through daily coordination with King County Metro and the Seattle Department of Transportation. Travel times for cars and buses during peak periods in the morning and afternoon have remained fairly steady – not just on SR 99 but on nearby arterials as well. So whether you've been leaving your house or work an hour earlier, riding your bike, or avoiding SR 99 altogether, we appreciate your efforts.

If you've driven the mile-long work zone during the day you might not have seen a lot of work happening and may have wondered, "What exactly are they doing in there?" We're here to give you an update on what's been accomplished so far.

As of now, crews have completed the following work, the majority of which has taken place at night and over the weekend, when we allow crews to close a second lane in each direction.
  • Placed approximately 1,600 feet of temporary concrete barrier to establish four separate work zones between the Aurora Bridge and Highland Drive.
  • Cut and removed approximately 1,600 square feet of pavement and 800 feet of existing concrete barrier to make room for the new sign structure foundations.
  • Drilled four underground shafts for the sign foundations. Each shaft is 4½ feet in diameter and extends 14 to 18 feet underground. Drilling work went quicker than expected and crews were able to reopen the lanes more than 24 hours ahead of schedule last weekend.
  • Began forming the actual foundations by placing rebar and pouring concrete into the shafts.
  • Began installing underground power and communications lines at two of the sign locations that will support electronic messaging systems and data collection tools.

So what work is left in Phase 1? Crews still need to:
  • Place concrete barriers around each foundation for additional protection and support.
  • Complete installation of underground power and communications lines.
  • Remove the temporary concrete barrier, restripe the lanes and restore SR 99 back to its original configuration.

The second phase of work is scheduled to begin mid-February and includes drilling, placing rebar and pouring concrete for one remaining sign foundation near Comstock Street. Phase 2 will require a localized closure in the southbound curb lane near Comstock Street for approximately three weeks. All northbound lanes will be reopened at that time. This work is not expected to significantly impact traffic.

If you would like additional information about the SR 99 lane closures or ongoing construction at the north end of the SR 99 tunnel, please visit our project website. Thank you again for your patience as we complete this work.

Friday, January 22, 2016

Your safety is our priority. We need your help to make our safety your priority

Yesterday, we almost lost an employee in a work zone. Fortunately, our employee is recovering at home and our partner, Washington State Patrol, is investigating the incident. This blog isn’t to talk about the details of what happened; rather, it’s to focus attention to where it needs to be: the road.

Each and every day, we – me included – travel all over for work, meetings, appointments and ultimately home to our loved ones. All too often we see people speeding or driving distracted, but when we drive, we must stay focused. In a split second, it could mean your life … or the life of someone else. 

We talk daily about safety. It’s our first priority in everything we do. Your safety is important and so is ours. Yesterday is a perfect example. We kept many passes closed because weather and avalanche danger simply made them too dangerous to cross. Is it inconvenient? Yes! But, we do it because we want everyone to get where they are going safely.

Your safety is our priority and we need your help to make our safety your priority. We need you to drive safely. Pay attention. Drive slowly in work zones. Limit distractions. Put down your phone.

Nothing is worth jeopardizing your ability to go home … or ours. We are committed to your safety and I need you to be committed to ours.

Thank you,
Secretary Lynn Peterson

Workzone Safety Statistics