Tag Archives: low tide

Swollen seas and a Tolkien tide

A Tolkien tide
Having been a fan of Tolkien’s faerie tales since I was chasing squirrels in the oaks and hickories of the heartland, it’s no surprise I’m excited to see the Hobbit. My dear Alejandra even bought me a ticket to the opening show at our local theater. Of course, that requires staying awake!

If you too have any intention staying up for a midnight cinematic premier, mother nature will provide a premier low tide (-3.6′ish) to fill the “I really should be going to bed now” hours with “Ooo’s” and “Ahh’s” in the beam of your light. For most of the inland Salish Sea, the tide will be in minus territory any time after 9:pm and bottoms out around around 11:pm. It’ll probably be wet and chilly, so dress well and feel free to share what cool things you see through comments or by  contacting me directly.

The wrack or debris line over this parking area indicates the peak of especially high storm tide in early December 2012. Photo: Jeff Adams

Swollen seas
‘Tis the season for storm surges.

The week before Thanksgiving, I saw the 12′ predicted high tide lapping on the beach as I walked off a ferry to West Seattle. A stream babbled north under the dock, well above the tide and buffered by large wood and another few feet of gravel/sand beach.

I traveled the same path a week later, when the predicted high tide was actually a few inches lower. However, the storm tide had swamped the beach logs and stream both, lapping in the vegetation of the recently restored shoreline. Numerous logs with cut ends had rolled and floated out into the bay – an example of the sub-par services cut logs provide when compared to their rooted and branched brethren.

You may also recall the heavy rain before Thanksgiving. Along with that came the surge that I observed and that you can see in the graph below. The actual water levels (red) pushed almost 2 feet higher than the predicted level (blue). The green shows the difference between the two. When predictions hold, the green line stays on zero.

Air pressure and predicted and actual water levels during 2012′s pre-Thanksgiving storms. http://tidesandcurrents.noaa.gov
Air pressure and predicted and actual water levels at The Battery Station, New York City, during Hurricane Sandy. http://tidesandcurrents.noaa.gov

Heaping on the water
Tides are predicted based primarily on the locations of the Earth, Moon and Sun. Those astronomical or predicted tides are the numbers we see in our tide tables, apps or calendars. We have a great deal of certainty as to where the heavenly bodies will be at any given time in the future, but back on our corner of the blue planet, long-range weather details are largely unknown. Consequently, we have no long-range ability to factor storm surges into our tidal predictions.

Storms, caused by the collision of colder northern air and warmer southern air, set our Pacific waters in motion. The warm air rises, lowering the pressure the atmosphere applies to the ocean and allowing the ocean to swell. That pressure-driven surge is accompanied by some level of  wind-driven surge, as the rising warm air also fosters stronger winds that pile the water up on the coastline.

Since our region is spared tropical cyclones (we seem satisfied with earthquakes and volcanoes), our storm surges are mild compared to what everyone watched the East Coast suffer during Hurricane Sandy (right). Still, it’s not unusual for our waters to surge 1 or 2 feet higher than expected during stormy seas.

Our strongest storms often strike in the winter, when we also have some of our highest predicted tides (see and be part of WA DOE’s King Tide photo initiative). Add 20 inches of storm surge to an already high tide, then throw in some high wind and waves… repairs to shoreline properties, roads, and utilities often follow. Factor in potential effects of climate change (a few inches of sea level rise, more intense storms), and the issue of storm surge becomes an important consideration with regards to shoreline infrastructure. Oh, and that kayak that you didn’t bother to tie up because it was 2 vertical feet above the highest predicted tide… (ouch!)

Our highest tide. Highest recorded water level at the Seattle, Puget Sound station. http://tidesandcurrents.noaa.gov

Tide fun courtesy of NOAA
If you enjoy exploring graphs and numbers, you can have some fun through NOAA’s Tides & Currents portal. You can even check out sea level changes over time and historical extremes. The “Seattle, Puget Sound” station’s highest recorded water level was in January 1983 at +14.48 (right). Not too bad considering our recent big surges were about +14. Certainly nothing compared to the extra 10 feet piled onto the east coast shorelines.

When you’re playing with the numbers and graphs, remember the -8hr conversion from GMT and a -7.94 feet conversion from the extremes section to make them comparable to what we’re used to seeing (based on mean lower low water [MLLW] as 0.0, instead of the station standard that’s 7.94 feet below MLLW).

Have fun exploring NOAA’s online tidal treasures and our last lowest tide of the year! And if you fall asleep at work or school tomorrow… you didn’t read this.

Jeff Adams is a Washington Sea Grant Marine Water Quality Specialist, affiliated with the University of Washington’s College of the Environment, and based in Bremerton. You can follow his Sea Life blog, SalishSeaLife tweets, FaceBook and video posts, send email to jaws@uw.edu or call at 360-337-4619.

 

Terrific Tides and Getting Crab Crazy!

Pulling a crab pot can require some muscle. Photo: Jeff Adams

Dust off the crab pots (both the one with holes and the one with boiling water), it’s crab season! The long awaited day has arrived (as of 7:00am today, 7/1), and many will feast on freshly caught crabs for the holiday. After all, Dungeness crabs are as Northwest’erican as espresso and apple pie. Don’t forget the red rock crab though. It’s tougher to crack, but abundant and mighty tasty.

Chris Dunagan shared a story on the recreational harvest this crab season, and Washington Department of Fish and Wildlife has a one stop recreational crabbing website with a 4 minute video, regulatory, harvesting, cleaning and cooking tips and more. A few things to note…

- A fishing license and crab endorsement are required. (Don’t forget you need to pay to get into Washington State Parks now.)
- You can keep up to 11 crabs a day!

  • 5 hard-shelled, male Dungeness crabs and
  • 6 hard shelled red rock crabs (male or female).

- Use pots (with degradable cords to prevent ghost fishing) or collect by hand.
- Don’t forget to RECORD AND REPORT your catch! (Says the guy who’s committed to doing his part for the fishery… and to not paying the $10 penalty again this year.)

While your on your way to or from your favorite destination, check out some of these excellent holiday weekend beach walks and events. Have a crabby day! JEff

A barnacle encrusted red rock crab. If you get a crab like this, you might as well eat the barnacles too... taste a bit like shrimp. Photo: Jeff Adams

This week’s minus tides for the Central Puget Sound (remember you may need to add up to an hour or more for out of the way fingers like Dyes Inlet, and much of South Puget Sound)…

  • 7/1 Fri; -2.6 ~11:30am
  • 7/2 Sat; -2.7 ~12:15pm
  • 7/3 Sun; -2.4 ~1:00pm
  • 7/4 Mon; -1.8 ~1:40pm
  • 7/5 Tues; -0.7 ~2:15pm

Kitsap Beach Naturalists
- Silverdale Waterfront Park, one of my favorite urban Kitsap beaches, Saturday July 2nd from 12:30-2:30pm
- Scenic Beach State Park, Seabeck, WA, July 2, Noon-2:00pm
- Fay Bainbridge Park, Bainbridge Island, WA, July 3, Noon-2:00pm

Harbor WildWatch (Gig Harbor and the south of Kitsap Peninsula)
- Kopachuck and Penrose State Parks, July 1, 10:30am-2:30pm
- Penrose and Joemma State Parks, July 2, 11am-3pm
- Kopachuck and Penrose State Parks and Narrows Park, July 3, 11:30am-3:30pm
- Kopachuck and Penrose State Parks, July 4, 12:30pm-4:30pm

Celebrate Oakland Bay – Family Fun with the Stars (site with link to flyer)
- Walker County Park, Shelton, July 3, 11am-4pm

Vashon Low Tide Festival
- Point Robinson Light Station and Park, July 2, 10am-3pm

South Sound Beach Naturalists
- Priest Point Park, June 2, 12:15pm – 3:15pm.
- Burfoot and Tolmie State Parks, June 3, 12:30pm – 3:30pm

Seattle Aquarium Beach Naturalists are on a variety of east Sound Beaches
- Richmond Beach, Carkeek Park, Golden Gardens, South Alki, Lincoln Park, Seahurst and Des Moines Beach Park, July 2, 11-2:30; July 3, 11:30-3; July 4, 12:30-3:30

I’m sure there’s more! Please share other opportunities through comments.

Jeff Adams is a Washington Sea Grant Marine Water Quality Specialist, affiliated with the University of Washington’s College of the Environment, and based in Bremerton. You can follow his Sea Life blog, SalishSeaLife tweets and videos, email to jaws@uw.edu or call at 360-337-4619.