From 8 June 1783 to 7 February 1784 the Laki fissure (Lakagígar) in Iceland‘s remote
highlands erupted. It released large amounts of gases (including 122 megatons of sulfur
dioxide) and produced the largest amount of lava (14.7 km3) of any eruption in the last
millennium, which together formed a dry and sulfuric fog. !
The Laki fissure is 27 km long and consists of 140 craters. Iceland is one of most active
volcanic zones, due to its location on top of the Mid-Atlantic Ridge and above a hotspot.!
The consequences for Iceland were catastrophic: The eruption caused a famine, which killed
almost a fifth of the population. The world outside Iceland did not know about the eruption.!
Fig. 8. Occurrence of the Laki
haze. (Map by Thordarson / Self
2003, fair use.)!
Fig. 7. Satellite image from 11 May 2010, the ash plume caused by
Eyjafjallajökull is carried towards Europe. Perhaps it looked similar in 1783.
(Image by NASA Goddard/MODIS Rapid Response Team, public domain.) !
Fig. 6. Painting of the flooding of the
River Main in Würzburg, southern
Germany, in February 1784. It was the
second highest flooding event there
since 1342. (In the public domain.)!
Fig. 5. Print of the “Great Meteor,“
which appeared on 18 August 1783.
(Print by Henry Robinson, Online
Collection, the British Museum, CC
Fig. 4. Illustration of the 5 February
1783 earthquake in Calabria and Sicily
(7.0 magnitude, XI Mercalli scale). The
print shows the destruction caused by
the earthquake. (In the public domain.) !
Katrin Kleemann is a doctoral candidate at the Rachel Carson Center for
Environment and Society / LMU Munich in Germany, where she studies
environmental history and geology. Katrin is the recipient of a fellowship of the
Andrea von Braun Foundation. This poster presentation has generously been
supported by a travel grant from VICS and from the Amerika-Institut at LMU.!
The photo shows a lava field produced by
the Laki fissure eruption in 1783. Today it
is covered by moss. (The image was taken
by Katrin Kleemann in August 2016.) !
Contact me via
About the Author
Impacts of the Laki Fissure Eruption of
1783 on North America
Katrin Kleemann, M.A.
Rachel Carson Center, LMU Munich, Germany
In the summer of 1783 the contemporaries in Europe gazed at the sky and observed an
unusual dry fog with a sulfuric odor that lasted for up to three months. Several extraordinary
phenomena characterized 1783: !
• an unusual heat!
• crop damage by sulfuric acid; sticky “honey dew” on some plants!
• a greater than usual number of thunderstorms !
• earthquakes and a tsunami in Italy!
• a newly emerging island off the coast of Iceland!
• a meteor passing over England and France!
• an exceptionally cold winter!
• ice drifts and flooding of central European rivers!
What had caused these bizarre occurrences? At the time, contemporaries were left alone to
contemplate these unusual events. It took one hundred years for the contemporaries to
connect the dots between the Laki fissure eruption and the dry fog, and importantly separate
some of those phenomena that were unrelated. !
Did you know? The ratification of the Treaty of Paris was delayed by the cold
winter that followed the eruption as the passage of ships, and therefore communication, was
hindered by ice and storms. The winters from 1783 to 1786 were not only severe in Europe,
in the eastern United States the winters were colder than average as well.!
• NW Alaska saw an extremely cold summer in 1783 (4°C below mean); oral Inuit
history remembers “the time summer time did not come;” with a significant
decrease in the local Inuit population (Jacoby 1999)!
• 1783-1784 was one of the longest winters in the eastern US; with snow in late April!
• this winter also saw the greatest snowfall ever in New Jersey!
• records show the longest period of below 0°C temperatures in New England and the
longest freezing over of Chesapeake Bay during this winter!
• Charleston Harbor froze over in February 1784, and ice skating was possible!
• the Mississippi River at New Orleans froze over (13-19 February 1784) and ice floes
appeared in Gulf of Mexico, 100 km south of New Orleans (all Ludlum 1966)!
It is unclear whether the dry fog was observable from North America; Hudson Bay records
and weather diaries from the US do not mention unusual skies in 1783. (Stothers 1996)!
The summer in North Alaska and the winters in the eastern United States were colder than
average. It remains to be answered whether the cold winters in Europe and North America
were in fact caused by the Laki fissure eruption. !
Several questions remain open at this point and need further investigation using North
American contemporary sources, such as:!
• How, if at all, did contemporaries in North America react to the news about the
extraordinary phenomena in Europe?!
• Was the discourse in North America influenced by the European one, for instance
did Americans fear living in a time of a subsurface revolution too?!
• Did the dry fog also cause excess mortality in North America?!
• Did sulfuric acid damage plants in North America?!
• Did sunsets and sunrises also appear blood red in North America?!
D’Arrigo, Rosanne, et al. “The Anomalous Winter of 1783-1784: Was the Laki Eruption or an Analog of
the 2009-2010 Winter to Blame?” Geophysical Research Letters 38 (2011).!
Jacoby, Gordon C., et al. “Laki Eruption of 1783, Tree Rings, and Disaster for Northwest Alaska Inuit.”
Quarternary Science Reviews 18 (1999):1365-1371. !
Kleemann, Katrin. “Speculating About the Weather: The Unusual Dry Fog of 1783.“ NiCHE, 2 Oct 2017. !
Kleemann, Katrin. “Volcanoes, Climate Change, and Society: History and Future Prospects.“
HistoricalClimatology.com Blog, 23 November 2017. !
Ludlum, David M. Early American Winters, 1604-1820. Boston: American Meteorological Society, 1966.!
Scarth, Alwyn. Vulcan’s Fury: Man Against Volcano. Hong Kong: World Print Ltd, 1999. !
Schmidt, Anja, et al. “Climatic Impact of the Long-Lasting 1783 Laki Eruption: Inapplicability of Mass-
Independent Sulfur Isotopic Composition Measurements.” Journal of Geophysical Research 117 (2012).!
Stothers, Richard B. “The Great Dry Fog of 1783.” Climatic Change 32 (1996):79-89.!
Thordarson, Thorvaldur, and Stephen Self. “Atmospheric and Environmental Effects of the 1783-1784
Laki Eruption: A Review and Reassessment.” Journal of Geophysical Research 108 (2003). !
Fig. 3. A map of Iceland‘s geology. (This map was created by Katrin Kleemann and is built upon
materials from Gingko Maps, CC BY 3.0 license.) !
3. Impacts on North America
4. Conclusions and Future Work
2. Consequences for Europe
Fig. 1 - 2. View of the Laki fissure from Mount Laki. Fig. 1 shows the SW and Fig. 2 shows the NE part, with the
Vatnajökull ice shield in the background. (Photos taken by Katrin Kleemann.) !