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Scientists Call Mt Rainier Most Dangerous Volcano

natureJune 4, 2026·210 words·2 min read

This is a B1 (intermediate) English article about scientists call mt rainier most dangerous volcano. Read the article below, then check the key words and test your understanding with 5 exercises. You can also listen to the audio and tap any word to see its meaning.

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Scientists Call Mt Rainier Most Dangerous Volcano
Scientists say Mount Rainier in Washington State is the most dangerous volcano in the United States. The main danger is not lava. It is a lahar a fast river of rock, mud, and melted ice. A lahar can move at over 100 miles per hour. It could reach three nearby towns in just 30 minutes. Up to 60,000 people in Pierce County, near Seattle, could be in danger.
Lahars do not need a volcanic eruption. Heavy rain, a sudden warm spell, or a broken dam can start one. Mount Rainier has 25 large glaciers slow rivers of ice. They hold more than five times as much ice as all other Cascade volcanoes combined. So a small amount of melting can cause a huge lahar. The wall of mud can grow hundreds of feet tall and travel over 50 miles.
This danger is real. In 1985, a lahar from a volcano in Colombia killed more than 23,000 people in just minutes. To stop the same thing happening here, the Cascades Volcano Observatory (CVO) has placed special sensors to detect lahars and earthquakes. Two years ago, over 45,000 students and staff joined a huge evacuation drill. They learned that running uphill on foot is the best way to stay safe.

Key Vocabulary

adj.
a fast river of volcanic mud, rock, and water
n.
a slow-moving river of ice
n.
the bursting out of a volcano
n.
a science center that watches something closely
v.
find out that something is there
n.
moving people from a dangerous place
adv.
up a slope
n.
a device that feels signals like shaking
n.
practice for an emergency
Vocabulary Translations· 9 words · 12 languages

Every definition is context-aware — translated based on how the word is used in this article, not a dictionary.

laharadj.

a fast river of volcanic mud, rock, and water

lahar (dòng bùn núi lửa)lahar (fluxo de lama vulcânica)ラハール(火山泥流)lahar (volkanik çamur seli)lahar (flujo de lodo volcánico)lahar (potok błota wulkanicznego)لاهار (سيل من الطين البركاني)lahar (vulkanische modderstroom)лахар (вулканический грязевой поток)火山泥流(lahar)라하르 (화산 진흙류)
glaciern.

a slow-moving river of ice

sông bănggeleiras氷河buzullarglaciareslodowceأنهار جليديةgletsjersледники冰川빙하
eruptionn.

the bursting out of a volcano

sự phun tràoerupção噴火yanardağ patlamasıerupciónerupcjaثوران بركانيuitbarstingизвержение火山喷发분출
observatoryn.

a science center that watches something closely

đài quan trắcobservatório観測所gözlemeviobservatorioobserwatoriumمرصدobservatoriumобсерватория观测台관측소
detectv.

find out that something is there

phát hiệndetectar検知するsaptamakdetectarwykryćيرصدdetecterenобнаруживать探测감지하다
evacuationn.

moving people from a dangerous place

sự sơ tánevacuação避難tahliyeevacuaciónewakuacjaالإخلاءevacuatieэвакуация疏散대피
uphilladv.

up a slope

lên dốcmorro acima, ladeira acima上り坂を、坂を登ってyokuş yukarıcuesta arribapod góręصعودًاbergopв гору沿坡而上오르막으로
sensorn.

a device that feels signals like shaking

cảm biếnsensoresセンサーsensörlersensoresczujnikiأجهزة استشعارsensorenдатчики, сенсоры传感器감지기
drilln.

practice for an emergency

cuộc diễn tậpsimulado, exercício訓練、避難訓練tatbikatsimulacroćwiczenie próbneتدريب محاكاةoefeningучение, тренировка演习훈련

Check Your Understanding

Question 1: Multiple Choice

Why is a lahar so dangerous for the towns near Mount Rainier?

Question 2: Multiple Choice

According to the article, what is the best way for people to stay safe from a lahar?

Question 3: Fill in the Blank

Mount Rainier has 25 large ______ that hold lots of snow and ice.

Question 4: Fill in the Blank

Special sensors can ______ lahars and earthquakes before they reach the towns.

Question 5: Put in Order

Put these ideas in the correct logical order.

1The lahar runs down the mountain and reaches three towns in 30 minutes.
2Sensors warn people, and they run uphill on foot to stay safe.
3Heavy rain or warm weather melts the ice on Rainier's glaciers.
4The melted ice mixes with rocks and mud to make a fast lahar.

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