El Salvador - GFDRR

6 | El Salvador: Damage, Loss, and Needs Assesment
It is difficult to establish a trend regarding whether the recurrence or frequency of these events is
increasing as a consequence of climate change processes, although their economic cost has undoubtedly
grown exponentially. Even on a partial basis (only those events that the country’s government has
requested are evaluated), the average annual impact of this type of disasters is around 160,000 people
affected, with damages of nearly US$470 million and losses of nearly US$220 million. Their weight in the
GDP is 4.2%, while damages represent over 20% of gross capital formation (GCF). Although this average
is biased by the large-scale events that occurred (Hurricane Mitch, the 1986 and 2001 earthquakes,
principally), these evaluations do not take into account the “everyday disasters” or small-scale events that
the country suffers each year—particularly recurring floods and landslides in the rainy season—, especially
affecting the most vulnerable zones in urban areas and disadvantaged agricultural producers, on slopes
and riverbanks that are regularly flooded.
TABLE 2. EL SALVADOR: STATISTICS OF EVENTS EVALUATED BY CEPAL, 1982–2005
Population affected Total (in millions of US dollars, 2007) Relation
of total
Deaths Direct Total Damages Losses
External
effect
impact to
preceding
GDP
Damages
with
respect to
preceding
GCF
Total events
evaluated 3,385 3,648,343 15,763 10,743 5,020 3,357 32.3% 160.5%
Average per
event 564 608,057 2,627 1,791 837 559 16.1% 80.2%
Average per
year during
the period 147 158,624 685 467 218 146 4.2% 20.9%
Source: CEPAL assessments (1982–2005).
B. NOVEMBER 2009 EVENT – CAUSES AND DESCRIPTION
The event that occurred on this occasion is associated with heavy precipitation that totaled over 450
mm in a three-day period (November 7 to 9, 2009), with a maximum intensity of 355 mm in a five-hour
period during which landslides occurred and rivers overflowed their banks. This figure corresponds to
nearly five times the average precipitation expected for the month of November. The lahars 7 that hurled
down over Verapaz, where the greatest numbers of deaths took place, occurred in the early morning
(around 2:00 a.m. on November 8, 2009).
7
A lahar (or mudflow) is a flow of mud moving down from the slopes of stratovolcanoes. In recent centuries, lahars have
destroyed more public or private property than any other volcanic process and have caused the losses of thousands of
human lives. Lahars, together with falling tephra, are the principal cause of risks associated with volcanoes. Lahars may
occur due to:
1. Intense rainy periods, not necessarily coinciding with periods of volcanic activity.
2. Glaciar fusion in the upper parts of a volcano during volcanic activity.
3. Emptying of a crater lake located at the top of a volcano.
4. Collapse of slopes due to prolonged hydrothermal alteration or earthquake.
Unlike landslides of debris, lahars are humid deposits where water influences both the genesis and the transport of the
remobilized mass (http://es.wikipedia.org/wiki/Lahar)