earth science

The Barrier

The Barrier is a earth science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand The Barrier rather than just read about it. In short: The Barrier is a lava dam retaining the Garibaldi Lake system in southwestern British Columbia, Canada. It is about 80 kilometres (50 miles) north of Vancouver in Garibaldi Provincial Park of New Westminster Land District.

Key takeaways

The Barrier belongs to earth science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect The Barrier to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of The Barrier from memory before moving on to harder problems.

Reference excerpt

The Barrier is a lava dam retaining the Garibaldi Lake system in southwestern British Columbia, Canada. It is about 80 kilometres (50 miles) north of Vancouver in Garibaldi Provincial Park of New Westminster Land District. The Barrier lies in the Cheakamus River watershed of the southern Coast Mountains where snow-capped mountains, diverse vegetation and rich geological history exist. Garibaldi Lake is the largest lake impounded by The Barrier; it has a length of 5.23 km (3.25 mi) and a width of 2.4 km (1.5 mi). The much smaller Lesser Garibaldi and Barrier lakes are also impounded by The Barrier. However, they lie within depressions on the surface of the lava dam rather than behind it. All three lakes are drained by Rubble Creek, a tributary of the Cheakamus River flowing northwest from the foot of The Barrier. The Barrier formed about 13,000 years ago when lava flowed into Rubble Creek valley. It then ponded and cooled against the retreating Cordilleran Ice Sheet, resulting in the lava flow being unusually thick. The source of the lava flow was Clinker Peak on the western shoulder of Mount Price, a stratovolcano reaching an elevation of 2,049 metres (6,722 feet). In 1855–1856, The Barrier was the source of a large rock avalanche that travelled down Rubble Creek valley to the Cheakamus River. This collapse of the lava dam created its current headwall; it rises about 500 m (1,600 ft) above the floor of Rubble Creek valley. The headwall has been highly unstable since the 1855–1856 landslide, having been the site of several rockfalls. Debris from these rockfalls has formed a talus deposit at the base of the headwall. Concerns about The Barrier's instability prompted the provincial government to declare the area immediately below it unsafe for human habitation in 1980–1981. This led to the evacuation of the small resort village of Garibaldi nearby and the relocation of residents to new recreational subdivisions away from the hazard zone. As of 2025, The Barrier merits consideration in future volcanic hazard assessments. This is particularly due to the presence of Garibaldi Lake, which would be released catastrophically if the lava dam were to ever give out.

Name This feature has been referred to as The Barrier since at least the 1910s. The name was adopted on the British Columbia map 2D on May 6, 1924, which referred to The Barrier as a mountain. On June 6, 1957, the name was adopted on the National Topographic System map 92G/14. Instead of referring to it as a mountain, The Barrier was referred to as a cliff on 92G/14. BC Geographical Names describes The Barrier as a cliff and a natural volcanic dam.

Geography

Location The Barrier is located about 80 kilometres (50 miles) north of Vancouver between the communities of Squamish and Whistler. It lies within Garibaldi Provincial Park, a more than 20,000-hectare (49,000-acre) protected area in the southern Coast Mountains. This wilderness park incorporates much of the Cheakamus River watershed and contains snow-capped mountains, diverse vegetation, iridescent waters, scenic vistas and rich geological history. The main territorial division in the area is New Westminster Land District which includes the southwestern portion of mainland British Columbia, as well as offshore islands and waterways.

Hydrology

Garibaldi Lake on the northern side of Mount Garibaldi is the main lake impounded by The Barrier. It lies within the heart of Garibaldi Provincial Park and is fed by meltwater streams originating from glaciers. With a length of 5.23 km (3.25 mi) and a width of 2.4 km (1.5 mi), Garibaldi Lake is the largest lake in Garibaldi Provincial Park. This 250-metre-deep (820-foot) lake has a water volume of 1 km3 (0.24 mi3) and a surface elevation of 1,470 m (4,820 ft). It is drained by Rubble Creek, which flows into the much smaller Lesser Garibaldi Lake. Lesser Garibaldi Lake lies within a depression on top of The Barrier where Rubble Creek follows a subterranean channel under the volcanic dam. Rubble Creek then reappears at the foot of The Barrier in a pair of springs before flowing northwesterly through a valley to the Cheakamus River 4.5 km (2.8 mi) downstream. At times of exceptionally high water, a part of Rubble Creek flows over the surface to Barrier Lake at the northwesternmost end of The Barrier. Rubble Creek then cascades over The Barrier into the lower valley.

Geology

Background The Barrier is part of the Mount Price volcanic complex, which also includes the 2,049 m (6,722 ft) high stratovolcano of Mount Price and the 1,983 m (6,506 ft) high stratovolcano of Clinker Peak on the western shoulder of Mount Price. This complex was formed by the eruption of lavas and pyroclastic flows during three periods of volcanic activity in the last 1.2 million years; the lavas and pyroclastic flows are andesitic and dacitic in composition. The Mount Price complex is the oldest eruptive centre in the Garibaldi Lake volcanic field, which also includes Cinder Cone, The Black Tusk and The Table. Volcanism throughout the Garibaldi Lake volcanic field has produced a broader range of volcanic rocks; among them are andesite, dacite, basaltic andesite and basalt. The volcanic field is part of the Garibaldi Volcanic Belt, which includes several other volcanic fields such as the Mount Garibaldi, Mount Meager, Mount Cayley, Bridge River and Squamish fields. Volcanism in the Garibaldi Volcanic Belt, which began about three million years ago, is the result of subduction along the western continental margin of North America.

Structure

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with The Barrier

Start with the simplest possible case. Write down what The Barrier claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In earth science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to The Barrier before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about The Barrier ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of The Barrier

In research: The Barrier appears in earth science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses The Barrier in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: The Barrier is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cliffs of Canada, Dams in British Columbia, Garibaldi Lake volcanic field, so understanding it makes those chapters shorter.
In everyday life: Look for The Barrier outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study The Barrier in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what The Barrier means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain The Barrier out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is The Barrier in simple terms?

Why does The Barrier matter?

Because it connects several earth science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study The Barrier?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on The Barrier.