Tuesday, January 29, 2019

Western Washington Juniper Forest in Washington Park

Juniper trees are a relatively uncommon tree in Washington State. Much of eastern Washington is too dry and/or too hot in the summer so that there are only a few isolated stands of Juniperus occidentalis (western) and even rarer Juniperus scopulorum (Rocky Mountain). The western junipers are limited to the Juniper Dunes Wilderness just north of the Snake River and a few isolated spots in the Snake River Canyon and Wallula Gap where the Columbia River cuts through the Horse Heaven Hills. The Rocky Mountain junipers are limited to small very isolated stands along the Columbia River from Chelan to Vantage.

Western Washington has Juniperus maritima (Adams, 2007). The south facing slopes in Anacortes' Washington Park is the largest stand I have observed.   

Juniperus maritima in Washington Park

The south slope of the park has an alpine feel with open meadows of grass and moss between stands of trees and rocky outcrops. The junipers are the dominant tree over large areas with scattered stands of Douglas fir and madrone.

View to the west toward with the southern end of Lopez Island in the distance and the Straight of Juan de Fuca.

View to the southeast and of Mount Erie

Burrows Pass and Burrows Island

Lichen covered rock and junipers

Serpentinite of the Fidalgo Ophiolite

Anacortes is well within the rain shadow of the Olympic Mountains. The relatively low rain fall and south slope aspect of the location contributes to the presence of the junipers. The junipers are also present on south slopes in dry areas of the San Juan Islands and Gulf Islands.

The geology of Washington Park provides another advantage to the junipers. Serpentinite chemistry is a harsh plant environment due to the unusual ration of calcium and magnesium as well as a lack of phosphate bearing minerals. That chemistry limits other trees and allows the junipers a competitive advantage as the junipers have a higher tolerance to these harsh conditions.

Monday, January 28, 2019

Punch Hole Cloud Over Northwest Washington

Punch hole cloud

We noted several holes in the high cloud deck this afternoon over northwest Washington. Several folks sent the images to Cliff Mass and I will leave the explanation to him Here.

Saturday, January 26, 2019

White Bluffs Landslides via Bjorstad

Bruce Bjornstad has been doing a series of drone YouTube videos on eastern Washington land forms. one of his latest is an ongoing large slope failure at White Bluffs.

The Ringold Formation lake sediments are sensitive to water inputs and have had large failures at multiple locations in Franklin County all along the White Bluffs as well as along one the south side of one of the ice age flood coulees. Bjorstad's video is on a reach of the bluffs I have not visited and is an area of the most recent large scale active movement. I have visited several of these slides and posted on them:




Tuesday, January 8, 2019

Toe Jam Fault, Bainbridge Island

I had a couple ventures on Bainbridge Island and drove up Toe Jam Hill Road. Toe Jam Hill is an elevated area of bedrock within the middle of the Puget lowlands. The bedrock has been uplifted along the Seattle Fault Zone. The location of the hill along the fault zone has given the hill a bit of lidar fame. Kitsap Public Utility District decided to use lidar to accurately map out watershed boundaries on the island. The surprise result result was the identification of a previously unrecognized fault scarp across the north flank of Toe Jam Hill.  

View up the hill towards the fault

View of fault scarp from Toe Jam Hill Road

From the ground and with the forest, the fault scarp is not a readily apparent feature. However, with lidar, the fault scarp is readily recognized.

The Toe Jam Fault is a fault splay within the Seattle Fault Zone. The trenching work along the fault has led to age dating of the offsets along the scarp (Nelson and others, 2003). That work is why Seattle as well as Bainbridge Island is deemed to have a higher earthquake risk than other areas in the Puget lowlands. Uplift associated with Seattle Fault has lifted the southern shore of Bainbridge Island creating a raised shoreline platform along the fringe of the south shore of the island.   

Lidar image from Puget Sound Consortium Mark ups by Reading the Washington Landscape

Note fault offset of Toe Jam Fault is down to the south and up on the north. The uplifted shoreline platform is south of the fault. The Toe Jam Fault is considered a back thrust within the broader Seattle Fault Zone which over all is up on the south and down on the north (Nelson and others 2014).  

Uplifted platform beach at Restoration Point, Bainbridge Island

Wednesday, January 2, 2019

Lake Claire and Lake Athabasca Delta Complex

After some family visiting, I had a mostly clear sky flight across Greenland and Canada. Lighting was such that the pictures below do not always capture the whiteness of the snow landscape, but I was able to capture some the unique land forms.

Birch River delta in Lake Claire, northeast Alberta, Canada

The hydrology of Lake Claire is complex. The Birch River flows into the lake from the west. The water outflow is to the east towards Lake Athabasca. However, the eastward outflow sometimes reverses and the lake receives intermittent flows from north when the Peace River floods. The floods are caused by high run off events from snow melt and or ice jams on the rivers.

The complex delta system between Lake Claire and Lake Athabasca is part of Wood Buffalo National Park, the second largest national park in the world. The delta complex and meander river systems are much better observed from the air, but the ecosystems that this landscape supports are why the park exits.  

Delta channels from Peace River overflow channels

Peace River with multi overflow channels. The river flows from the upper left to the right.  

Multiple overflow channels between the river and delta
This area is rich beaver, buffalo and crane habitat  

Just to the east of the Peace River moraines from the last glacial period form narrow ridges with low areas inundated with water either as lakes or wet meadows (now frozen)

European fur trappers entered this area by the 1780s and established a fort on the shores of Lake Athabasca near the delta. The waterways acted as a highway and were filled with rich beaver hunting. From there and other posts, fur companies continued to push west seeking more fur country and pushed into what is now Washington State in the early 1800s.