Jökull - 01.01.2021, Qupperneq 87

Álftaver’s experience of the 1918 Katla eruption
people expect to experience during the next eruption.
The stories provide meaning, with the descriptive de-
tails placed in the environment present day residents
know and understand. There is no doubt that the de-
scriptions from Álftaver farmers, of their experience
of the 1918 Katla eruption, have influenced current
knowledge and perceptions.
This inherited, experiential knowledge substan-
tially influences people’s willingness to comply with
emergency response strategies and evacuation plans.
Local residents have considerable, insider’s knowl-
edge of Katla eruptions and its associated hazards
but prevalence of experience in their representation
of risks make them reluctant to accept scenarios that
differ from how past events unfolded. This includes
complying with emergency response plans that do not
consider other hazard risks such as tephra and light-
ning.
Notably, officials have adopted local advice and
made room for the sheltering-in-community option –
Plan B for Álftaver. However, it appears that local res-
idents were not involved in the development of Plan B,
despite the critical knowledge they have of their local
area from both a social and environmental perspec-
tive. At the very least, this information needs to be
socialised with the local population so that it is clear
what Plan B means and under which circumstances
it should be activated so that there are no surprises
to anyone. Furthermore, sheltering-in-community re-
quires a high-level of preparedness and, self-reliance
and self-sufficiency of those residents who choose to
do so (Whittaker et al., 2017). Residents therefore
need adequate time to prepare themselves to imple-
ment Plan B and remain self-sufficient for any given
length of time until the risk (posed by jökulhlaup,
lightning and/or tephra hazards) has passed.
It would also be beneficial to compliment official
advice with the detailed descriptions from 1918. The
oral stories add a more human aspect to risk assess-
ments and, they can be used to bring emergency re-
sponse strategies to life.
Of course, one should not rely solely on the 1918
experience for predicting the inundation extent of fu-
ture events, the flood routes, and flow arrival times at
specific locations. The simulations (Kjaran and Hólm,
2006) upon which the early response plan was built
suggest that Álftaver could be reached by flood water
at a faster rate than that which occurred in 1918, if key
scenario 2 (Table 2) were to happen. Also, a differ-
ent interplay between the flood conveyance routes on
Mýrdalssandur may occur, as the front of Kötlujökull
recedes due to climate change (e.g. Sigurðsson, 2010)
and subglacial topography turns into proglacial land-
scapes. One cannot exclude for instance that the north
route (Figure 2) might become deactivated in the near
future. During a future eruption, this would result in
all floodwater surging on the outwash plain through
the middle and south routes, in a similar fashion as in
1823 and 1860 (see Larsen, 2018).
Clear, concise, transparent and ongoing commu-
nication is therefore critical at all stages of develop-
ing and implementing emergency response strategies.
And ongoing work is needed, given Katla’s contin-
ued unrest and the length of time since the last con-
firmed eruption in 1918, which historically speaking,
is a long time between Katla eruptions (Icelandic Me-
teorological Office (Veðurstofa Íslands), 2016). Au-
thorities responsible for the design and organisation
of such plans must collaborate with local residents to
ensure all parties fully comprehend the factors that
impact decision-making processes. From a residents’
perspective, this paper has highlighted many environ-
mental factors that will influence public response to
evacuation orders. For example, residents’ decision-
making will be influenced by visibility – whether it
is day or night, the weather is bad, or tephra fall is
impacting the area. These findings underscore the im-
portance for combined scenario modelling to incor-
porate differing environmental conditions as well as
other hazard risks alongside of jökulhlaups. As re-
ported by Barsotti et al. (2020), tephra fall alongside
flood hazards from a Katla eruption, is likely to cause
disruption to road travel in the region.
Of equal importance is the consideration of so-
cial factors that impact decision-making. Bird et al.
(2011) and Bird and Gísladóttir (2012) revealed that
alongside the environmental factors, some Álftaver
residents planned not to evacuate so that they could
remain on-hand to care for their livestock. Non-
compliance to evacuation orders is not unique to
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