Mudflows and Landslides in Vargas, Venezuela, 1999
Background info:
o December 1999
o Vargas → mountainous and coastal region in
northern Venezuela → lies on Caribbean Sea,
separated from Caracas by Avila mountains
Causes:
o Extreme rainfall → December 14-16: 911 mm of water fell in 52 hours, equivalent to
a year’s annual rainfall → exceeded 1000-year probability rainfall event→
continuous rainfall for 37 days → unexpected as rainy season is usually May-October
o Urban growth → led to development and
extensive urbanisation on top of the alluvial
deposits from previous floods and flows → high
risk area → populated by many shanty towns as
it is some of the only flat land in the area
o Geology → bedrock mainly made up of layers of
unconsolidated metamorphic rock → silty and
clayey→ weak and susceptible to landslides
o Steep mountain slopes → loose sediment → narrow coastal outlet which is
urbanised → deforestation of slopes by locals
Impacts:
o Primary:
▪ Thousands of landslides triggered → as they slid down the slopes and picked
up water they turned into mudflows and debris flows
▪ 8,000 homes and 700 apartment buildings destroyed
→ displaced around 75,000 people
▪ 1/3 of the Caraballeda fan was inundated by the flows
→ 60 km of coastline affected
▪ Death toll considered between 30,000-50,000 → only
1,000 bodies recovered; the rest were swept to sea by the
mud or buried by the landslides
▪ Total economic losses estimated at $1.79 billion
dollars
o Secondary:
▪ Public services completely disappeared in some areas
→ water, electricity, sewage, phone lines, roads and
bridges
▪ Places left with no food or drinking water for months
→ forced to evacuate
▪ Looting and sacking → forced implementation of
martial law
▪ Risk of cholera and malaria epidemics and
leptospirosis → contaminated water sources attract mosquitos and rats
Background info:
o December 1999
o Vargas → mountainous and coastal region in
northern Venezuela → lies on Caribbean Sea,
separated from Caracas by Avila mountains
Causes:
o Extreme rainfall → December 14-16: 911 mm of water fell in 52 hours, equivalent to
a year’s annual rainfall → exceeded 1000-year probability rainfall event→
continuous rainfall for 37 days → unexpected as rainy season is usually May-October
o Urban growth → led to development and
extensive urbanisation on top of the alluvial
deposits from previous floods and flows → high
risk area → populated by many shanty towns as
it is some of the only flat land in the area
o Geology → bedrock mainly made up of layers of
unconsolidated metamorphic rock → silty and
clayey→ weak and susceptible to landslides
o Steep mountain slopes → loose sediment → narrow coastal outlet which is
urbanised → deforestation of slopes by locals
Impacts:
o Primary:
▪ Thousands of landslides triggered → as they slid down the slopes and picked
up water they turned into mudflows and debris flows
▪ 8,000 homes and 700 apartment buildings destroyed
→ displaced around 75,000 people
▪ 1/3 of the Caraballeda fan was inundated by the flows
→ 60 km of coastline affected
▪ Death toll considered between 30,000-50,000 → only
1,000 bodies recovered; the rest were swept to sea by the
mud or buried by the landslides
▪ Total economic losses estimated at $1.79 billion
dollars
o Secondary:
▪ Public services completely disappeared in some areas
→ water, electricity, sewage, phone lines, roads and
bridges
▪ Places left with no food or drinking water for months
→ forced to evacuate
▪ Looting and sacking → forced implementation of
martial law
▪ Risk of cholera and malaria epidemics and
leptospirosis → contaminated water sources attract mosquitos and rats
