Tyler Wynn
The Puget Sound region has a rich glacial history, with ice sheets repeatedly advancing and retreating over the area. During the Vashon Glaciation, a lobe of the Cordilleran Ice Sheet, known as the Puget Lobe, covered the region in ice. This glacial activity left behind a unique landscape, including proglacial lakes, drumlins fields, and sedimentary deposits. While the region experiences colder temperatures due to its proximity to the Pacific Ocean, it is unclear if ice forms directly in Puget Sound. Occasional cold spells can cause ice and snow in the area, and glaciers have been known to form in mountainous regions with persistently cold temperatures and regular snowfall.
| Characteristics | Values |
|---|---|
| Ice formation | Ice sheets have repeatedly advanced and retreated from the Puget Sound region |
| Glacial period | Vashon Glaciation, also known as Vashon Stadial or Vashon Stade |
| Vashon Glaciation period | 19,000 - 16,000 BP (Before Present) |
| Vashon Glaciation depth | 1,600 metres (1 mile) at the Canada-US border, 1,000 metres (3,300 feet) in Seattle, and 200 metres (660 feet) at the glacier's terminus in Tenino |
| Vashon Glaciation rate of retreat | 340 metres (1,120 feet) per year |
| Formation of lakes | Glacial Lake Russell, Glacial Lake Snoqualmie, and Glacial Lake Bretz |
| Cause of cold spells | Cold air from the interior of the continent |
Explore related products
What You'll Learn
The Vashon Glaciation
During the Vashon Glaciation, the Cordilleran Ice Sheet advanced southwards at a rate of about 135 metres (443 feet) per year. Around 18,350 BP, the Puget Lobe blocked the Puget Sound from reaching the Strait of Juan de Fuca, turning the Puget Sound into Glacial Lake Russell. By around 17,950 BP, the glacier reached present-day Seattle. The Puget Lobe remained at its maximum extent in the vicinity of present-day Tenino from around 16,950 BP to around 16,850 BP, a total of about 100 years. The ice depths were about 1.6 kilometres (0.99 miles) at the present-day Canada-US border, 1,000 metres (3,300 feet) in Seattle, and 200 metres (660 feet) at the glacier's terminus in the Tenino area.
As the Vashon glacier receded, a series of proglacial lakes formed, filling the main trough of Puget Sound and inundating the southern lowlands. Glacial Lake Russell was the first such large recessional lake, extending from the vicinity of Seattle in the north to the Black Hills, where it drained into the Chehalis River. The second major recessional lake was Glacial Lake Bretz, which also drained into the Chehalis River until the ice sheet retreated, allowing the lake's water to drain north into the Strait of Juan de Fuca. The melting retreat of the Vashon Glaciation eroded the land, creating a drumlinoid ridge field of hundreds of aligned drumlin hills. Lake Washington, Lake Sammamish, Hood Canal, and the main Puget Sound basin were all altered by these glacial forces.
Trail Cam Videos: Capturing Nature's Sounds and Sights
You may want to see also
Explore related products
![Ice Age (2-Disc Special Edition) [DVD]](https://m.media-amazon.com/images/I/51y1HjsyM2L._AC_UL320_.jpg)
The Cordilleran Ice Sheet
The rapid retreat of the Cordilleran Ice Sheet is of particular interest to glaciologists and anthropologists. Glaciologists are studying the different patterns of melting in marine-terminating glaciers (those whose margin extends into open water without seafloor contact) and land-terminating glaciers (those with a land or seafloor margin). The western marine-terminating margin of the Cordilleran Ice Sheet retreated much faster than its southern, land-terminating front, resulting in fewer glacial landforms in the west compared to the south and east.
The collapse of the western front of the Cordilleran Ice Sheet has also been proposed as a possible route for early human migration into the Americas. This hypothesis suggests that humans crossed the Beringian Land Bridge during the Last Glacial Maximum and then migrated amid the retreat of the Cordilleran Ice Sheet's western front and the Laurentide Ice Sheet's eastern front. The rapid melting of the Cordilleran Ice Sheet, which likely occurred within four thousand years or less, also contributed to the topography of Eastern Washington and the creation of numerous glacial landforms across western Canada.
Cash Rebates: Smart Business Strategy or Costly Mistake?
You may want to see also
Explore related products
![Ice and rain sound [DVD] JAPANESE EDITION](https://m.media-amazon.com/images/I/51e4sBQ7kBL._AC_UL320_.jpg)
Glacial Lake Snoqualmie
The Puget Sound region has a rich glacial history. The area was covered by the Cordilleran Ice Sheet, which advanced and retreated over the Puget Lowland at least seven times during the Quaternary Ice Age. This ice sheet was about 3,000 feet (910 m) thick near Seattle and nearly 6,000 feet (1,800 m) thick at its deepest point. The most recent period of extremely cold climate in the region is known as the Vashon Glaciation, which lasted from around 19,000 to 16,000 years ago. During this time, glaciers covered the entire Salish Sea, as well as present-day Seattle, Tacoma, and Olympia. The Vashon Glaciation began after the planet's Last Glacial Maximum, a time when glaciers were retreating throughout most of the world but were growing in Western Washington.
The retreat of the Vashon glacier left behind a series of proglacial lakes, the first of which was Glacial Lake Russell. This lake extended from the vicinity of Seattle in the north to the Black Hills, where it drained into the Chehalis River. As the glacier retreated further, Glacial Lake Russell became connected to the Strait of Juan de Fuca, turning into a saltwater body known as Puget Sound. The second major recessional lake was Glacial Lake Bretz, which also drained into the Chehalis River until the melting of the ice in the Chimacum Valley allowed its waters to drain north into the Strait of Juan de Fuca.
Another notable glacial lake that formed during this time is Glacial Lake Snoqualmie. This large lake formed over North Bend and the Snoqualmie Valley. Tokul Creek, a tributary, formed a thick underwater delta in the lake as its sediments poured into it. When the Puget Lobe retreated, Glacial Lake Snoqualmie drained to the west, and the Snoqualmie River attempted to follow its original channel. However, the river's path was blocked by delta deposits from Tokul Creek, forcing it to flow over a narrow band of rocks from an eroded volcano further south. Today, Snoqualmie Falls flows over this volcanic rock, and the ongoing cataract recession is rapidly eroding the rocks.
Sound Frequencies: Can They Influence Slot Machine Outcomes?
You may want to see also
Explore related products
The Quaternary Ice Age
During the Vashon Glaciation, the Cordilleran Ice Sheet, which included the Puget Lobe, covered the Puget Sound region with an ice sheet about 3,000 feet (910 m) thick near Seattle and nearly 6,000 feet (1,800 m) thick at its deepest point. The Vashon ice sheet extended south of Olympia to near Tenino and covered the lowlands between the Olympic and Cascade mountain ranges. The climate in Western Washington during this time was much colder and drier than it is today. Pollen data from Battleground Lake in southwest Washington shows that annual temperatures were about 6 ± 1 °C (10.8 ± 1.8 °F) colder than present, with significantly less precipitation.
The Vashon Glaciation began after the planet's Last Glacial Maximum, when glaciers were retreating throughout most of the world but were growing in Western Washington. The Cordilleran Ice Sheet advanced southwards at a rate of about 135 metres (443 feet) per year. Around 18,700 years ago, the Puget Lobe blocked the Puget Sound from reaching the Strait of Juan de Fuca, turning the Puget Sound into Glacial Lake Russell. As the glacier retreated, Glacial Lake Russell drained into the Strait of Juan de Fuca, and the basin filled with seawater, becoming the saltwater body of Puget Sound again.
The retreat of the Vashon Glacier also resulted in the formation of Glacial Lake Snoqualmie over North Bend and the Snoqualmie Valley. When the glacier retreated, Glacial Lake Snoqualmie drained to the west, and the Snoqualmie River was forced to flow over a narrow band of rocks, forming Snoqualmie Falls. The melting retreat of the Vashon Glacier also created a drumlin field of hundreds of aligned drumlin hills and altered Lake Washington, Lake Sammamish, Hood Canal, and the main Puget Sound basin. The Puget Lobe of the Cordilleran Ice Sheet advanced and retreated over the Puget Lowland at least seven times during the Quaternary Ice Age, leaving behind rocks, sediments, and other geologic clues that tell the story of ice, proglacial lakes, and flooding in the region.
Dusty's Castle: A Quiet or Noisy Affair?
You may want to see also
Explore related products
The formation of proglacial lakes
Ice-dammed lakes
Ice-dammed lakes are formed when a glacier blocks a river, causing the water to back up and create a lake. These lakes are dependent on the existence of ice and are typically short-lived. They are associated with the ice margin of a glacier, and their formation rate is influenced by glacier movement and ice accumulation.
Moraine-dammed lakes
Moraine-dammed lakes are often associated with glacial retreat. They are formed when the front of a glacier detaches and leaves behind a moraine, which acts as a dam. These lakes can occupy areas previously filled by ice or meltwater and may outlive the glacier itself.
Debris flow-dammed lakes
Debris flow-dammed lakes are a result of slope failure in the surrounding bedrock caused by the removal of bedrock material by the glacier.
Bedrock dammed lakes
Bedrock dammed lakes are formed in depressions left by retreating glaciers. They are filled with meltwater and can persist long after the glacier's disappearance.
High-Pitched Noises: A Rat's Worst Nightmare?
You may want to see also
Frequently asked questions
Ice has formed in the Puget Sound region. During the Vashon Glaciation, the Cordilleran Ice Sheet covered the Puget Sound region with an ice sheet about 3,000 feet (910 m) thick near Seattle, and nearly 6,000 feet (1,800 m) thick at its thickest point.
The Vashon Glaciation, the most recent period of extremely cold climate in the Puget Sound region, lasted from about 19,000 to 16,000 years ago.
The Vashon Glaciation was the most recent period of extremely cold climate in the Puget Sound region, during which glaciers covered the entire Salish Sea as well as present-day Seattle, Tacoma, Olympia, and other surrounding areas.
