June 07, 2009

The Aftermath

The marine push event of last Thursday appears to have resulted in the deaths of three individuals...all of which were on the water that evening. Strong marine pushes generally follow periods of above normal temperatures...which tempt people to get on the water. It is easy to forget how quickly things can change around here.

And lets be honest about the forecast. The official predictions and model forecasts were clear that there was going to be a push, but no one expected it to be as strong as it was. I have studied these events extensively and have published several papers on them and it was only in the hour or two before that I understood how severe it would be (thus my blog entry about "all hell breaking loose." ) The key warning was the increase in the onshore pressure difference early that evening to unprecedented levels. Would it be useful for my profession to create a warning capability based on this pressure difference that was available on the web? Or the NWS could put out a warning on their NOAA weather radio on that basis?

This event has stimulated intense debate in my department. To what degree were the extraordinary winds the result of the unusual onshore pressure gradient and to what degree was the gust front propagating north from the thunderstorms in Oregon important. My gut feeling is the former was key. However, I plan on starting a detailed investigation of this event to really understand its origins.

Finally, a coastal weather radar would have been very useful for understanding what happened. Rain was falling on the southern WA and northern OR coasts and would have allowed the radar to paint out the winds.


  1. I love that like any dedicated scientist, your first response to a tragedy is to study it and figure out what went wrong. I wish you good effects from your efforts.

    Thanks also for mentioning the deaths of those individuals. It's easy to forget that strong weather can be dangerous, and I think it's important to recognize that and keep a reality check.

    As for our weather: I was surprised to see a NWS forecast for partly sunny skies and highs in the 70s this week. It seems too nice for a June gloom. What's your thought?

  2. One interesting thing about being a weather buff is the fact that phenomena that we witness as intense, interesting and sublime can be deadly to people in it's path but I'm still gonna enjoy it.

  3. Very interesting. I have had an experience with a wind event on a fire in Northern California. Typical sunny hot day in the Sierra Foothills. Not a cloud in the sky and up-slope diurnal light winds. Miles away over the Sierra Crest (donner summit area) a large cell of thunderstorms where moving north. The downburst from the storm followed the American River drainage for miles down into the foothills and "all hell broke loose". We went from a calm sw wind to a 50mph east wind that blew our fire to hell. Not only did it bring wind but drier air as well. It was like a flash flood of wind. We didn't see it coming.

  4. there was nothing on the local news weather there was going to be a push like what happened. Just like they never reported the weather system that would bring the floods to lewis county ( seattle magazine reported)

  5. Your Blog today poses an interesting question. I too was saddened to hear about the loss of life during the event (I would like to note that a couple did lack personal flotation devices.) As boaters we have often been frustrated by the lack of notice about these significant abrupt pushes. Last year we were caught in a similar scenario near Whidbey Island in a sailboat and hardly hard time to trim the sails!
    It appears to me that we live in a meteorological wonderland with a vast array of potential weather patters that makes it almost impossible to warn about these events…I would love to find out that I am wrong and enjoy accurate warnings!.

  6. The most important lesson here is to practice good seamanship all the time, even when it's sunny and warm. If you're on a sailboat that means having your sails ready to go at anchorage, having your reefing gear set up (if you can't put a reef in your main in 2 minutes, something is wrong), and having your anchor system ready to go.

    The winds that came up were strong, but not that strong. 25 knots with some stronger gusts are really not that crazy of conditions. This is where being prepared and good seamanship really come into play. While more accurate weather prediction is important, nothing can make up for skill and prudence on the water.

  7. Some of these boaters are just accidents waiting to happen. In the Bellingham incident, the boater had six people in an 18-foot boat. That's just way too many. If for some reason you ever needed to put six people in an 18-foot boat, they should all be wearing life jackets at all times.

    I spent many years sailing on Puget Sound but honestly, since moving to the woods and learning how much stuff falls down in a strong wind, I think it's safer to be a wise sailor on Puget Sound than it is to walk through the woods in a strong storm.

  8. Even the most useful "Nowcast" is only a tool, available to those who look for it, or happen to turn on weather radio. Not to cast aspersions on the dead, but does anyone think they looked for the sudden change in the weather? It was a beautiful if warm day, and even with my foreknowledge of the change coming I was a little taken aback by the suddenness (not having caught Cliff's update). But I was only sitting on my deck watching cedar needles fall into my glass of wine (though I did strike the deck umbrella before the zephyr hit).

    When sailing one must maintain constant vigilance and look fore and aft constantly because unexpected stuff happens. A more casual sailor may not have even glanced at the weather forecast or taken it seriously anyway. Look into the cause, Cliff, but wonder more if these folks would have seen the warnings anyway.

  9. I went kayaking with my 5-year old that evening, but fortunately came in before the push hit. I'm an experienced sailor and knowledgeable about marine pushes.

    Went kayaking after checking the NWS and marine forecasts. Checked the sky and conditions before and in all directions while out.

    Had no idea the push would be so strong. Would not have gone out if I knew.

    "Would it be useful for my profession to create a warning capability based on this pressure difference that was available on the web? Or the NWS could put out a warning on their NOAA weather radio on that basis?"

    Absolutely on NOAA weather radio! When we are on our sailboat or kayaks we do not have internet access, but we do have marine band radios. We even have a NOAA emergency alert radio at the house.

    Web alerts are helpful sometimes and would have been good before we went kayaking because we had been home, with internet access, all that day and evening.

  10. Although if you are including the two deaths in Bellingham it is quite clear that the young people who were amongst 6 people and a dog in a 16 foot sailboat sailing after midnight without anyone wearing a life jacket were being highly irresponsible. I doubt they checked the forecast before sailing. Plus, they left the island they were visiting (Chuckanut Island) after the marine push started, so they already knew about the wind. I know several of the survivors - it was very sad, but also very irresponsible. The wind tipped them over, but their lack of responsibility killed them.

  11. Sailing involves a certain level of risk that one can greatly reduce through skill and vigilance. Deficits in the latter two characteristics will not be overcome with increasing expenditure of public funds. Also the drunken driver approaching you in the other lane will always be a greater risk than a storm coming in from the coast.

  12. I think it was the push up from OR - The two systems - Low from the south and High from the North crashing - We paraglider pilots were wathching them for a week -
    Raw video at

  13. The other death, the man in Lake Washington near Kirkland was unfortunate, but again, not 100% a weather problem. Both boaters appeared very inexperienced. "Lost?" as reported in the paper along a shoreline in a major metropolitan area. It's hard to understand their actions unless they severely under the influence. We are lucky both of them didn't die.

    The kids in Bellingham bay, after midnight sailing? Risky at best and with the wind come up, staying put would have been the lifesaver. I've been in 18ft sailboats that can hold 6, but for most boats that size the upper limit is 4. Still if they had waited an hour or so, the front would have passed by and they would have been able to come home safely.

  14. Prof. Mass, some discussion of a developing El Nino pattern according to NOAA. How will this affect our summer to fall weather?

  15. well slap me silly its getting very dark and cloudy here in chehalis and the radar shows a nice healthy cell.. hopefully we will have a t-shower :)

  16. Cliff,
    Speaking about weather-related disasters, I wonder how much you've been following the Air France 447 discussions.

    Here's a FASCINATING page where they are exhaustively reviewing the weather that the plane encountered.


  17. I am told that Cmano Island gets no thunderstorms at all., which is hard to beleive. Is this true?

  18. Those winds were definitely gust front/shower outflow from the showers moving north. Happens ALL the time east of the Rockies... not sure how you can call it the marine push event.

    and where were these extraordinary winds? here in Seattle we had a nice breeze that made things feel much better than they had, but definitely not anything windy. Learn about weather in the Plains and Midwest if you want windy.


Please make sure your comments are civil. Name calling and personal attacks are not appropriate.

New Podcast: Memorial Day Weekend Forecast and More on Western Washington Wildfires

This weekend will be a mixed bag west of the Cascade Crest but warm over eastern Washington.  The predicted high temperatures for the next f...