Jökull - 01.01.2021, Page 84

Gísladóttir et al.
DCPEM-NCIP, and numerical simulations of result-
ing jökulhlaups performed by the engineering com-
pany Vatnaskil (Hólm and Kjaran, 2006).
Simulations of two key jökulhlaup scenarios (Ta-
ble 2) were presented to the local population in 2006
(Magnús Tumi Guðmundsson, personal communica-
tion, July 7, 2020) as well as an evacuation map pre-
pared by DCPEM-NCIP that builds on the results
of the simulations. One could not single out, from
the evacuation map, any of the modelled scenarios:
the scenario-based inundation extents were combined
into a single inundation area; flow travel times were
also combined to show the least flow travel times one
can expect on the outwash plain, all simulations be-
ing considered (see Figure 5). The inundation extent
and flow travel times obtained from the combined sce-
narios do not depict, strictly speaking, a worst case
among the hazard scenarios simulated–they exceed
those of each scenario considered separately–but were
used by DCPEM-NCIP as a conservative, out-of-
an-abundance-of-caution reference in the contingency
plan (Ágúst Gunnar Gylfason, personal communica-
tion July 8, 2020). The evacuation map was eventu-
ally featured in information brochures intended for lo-
cal residents and tourists visiting the region (DCPEM-
NCIP 2006a, 2006b). The brochure intended for local
residents was distributed in 2006 to every home in ar-
eas exposed to jökulhlaup hazards.
To gauge its effectiveness, implementation of the
plans was rehearsed in March 2006 with residents and
all agencies responsible for emergency response pro-
cedures (Bird et al., 2011). As per the plan for Álfta-
ver, residents received a telephone call on their land-
line or a notification (SMS) to their mobile phones,
with a message from DCPEM-NCIP informing them
that they had 30 minutes to evacuate the area and go
to the emergency relief centre in Kirkjubæjarklaustur
(Figure 5 – inset map). Police at Kirkjubæjarklaustur
were to ensure compliance with the evacuation order,
rather than the responsibility resting with the local res-
cue team in Álftaver.
Research by Jóhannesdóttir and Gísladóttir (2010)
showed that Álftaver residents were confused and
concerned about emergency response strategies that
had been developed prior to 2006. In follow-up to
Jóhannesdóttir and Gísladóttir (2010) research, Bird
and Gísladóttir (Bird et al., 2011, Bird and Gísla-
dóttir 2012) have captured Álftaver residents’ current
knowledge, perceptions and planned behaviour in re-
lation to Katla, its associated hazards, the 2006 evac-
uation exercise and in light of their experience of the
2010 Eyjafjallajökull eruption. The next section sum-
marises the key findings of that research.
Table 2. Key jökulhlaup scenarios presented to the
public in 2006 for an eruption within the Katla
caldera and jökulhlaup beneath Kötlujökull (personal
communication, Magnús Tumi Guðmundsson, Jan-
uary 26, 2021). The North, Middle and South con-
veyance routes on Mýrdalssandur are shown on Fig-
ure 2. – Helstu sviðsmyndir jökulhlaupa undan Kötlu-
jökli í tengslum við Kötlugos sem voru kynntar íbú-
um í Álftaveri árið 2006 (persónulegar upplýsingar
frá Magnúsi Tuma Guðmundssyni, þann 26. janúar,
2021). Norður-, mið- og suðurleiðir jökulhlaups á
Mýrdalssandi eru sýndar á 2. mynd.
Scenario Conveyance Peak Historical
routes on discharge event
Mýrdalssandur (m3/s)
South 250,000
1 Middle 15,000 1918 CE
North 35,000
South 50,000 Might have happened
2 Middle 200,000 during the 934 CE
North 50,000 Eldgjá fissure eruption.
CURRENT PERCEPTIONS AND
PLANNED BEHAVIOUR IN RELATION
TO EMERGENCY RESPONSE
STRATEGIES
Everyone interviewed in the Álftaver district was fa-
miliar with the history of Katla’s eruptions and the as-
sociated dangers (Bird et al., 2011). Residents had
familiarised themselves with stories of Katla erup-
tions and, the experiences of Álftaver farmers in 1918
had been passed down the generations. About half of
the people interviewed believed they were in greatest
danger due to the outburst floods, but residents also
considered risks from tephra and lightning, based on
82 JÖKULL No. 71, 2021