Volcanic ash on an topped-over iceberg on the Icelandic glacier lagoon

Tipped-over icebergs reveal their meltwater forms filled with volcanic ash on the frozen glacier lake lagoon Jökulsárlón during the winter of Iceland. Access to the icebergs on the glacier lagoon requires a chance meeting of a variety of conditions.
First, a sequence of low-pressure systems embedded in the mid-latitudinal westerly atmospheric flow over the North Atlantic Ocean brought vast amounts of rainfall to southern Iceland. The rain melted the snow cover on the icebergs and cleaned their surface to reveal their deep blue color. Second, the moving weather pattern changed to a stationary blocking situation with a stable low-pressure system to the northeast of Iceland, which continuously brought cold air from the Arctic to Iceland. Third, this cold air flow was blocked by the 1725 m (5659 ft) high ice cap of Vatnajökull. It forced the air to lift and overflow the ice cap at high speed. This lifting caused large quantities of snow to fall in the north of Iceland. In southern Iceland, by contrast, this weather caused a sustained foehn effect with sunny weather. Fourth, and this quite contrary to the intuition of the warming effect of the foehn winds, this locally led to enduring gusty and ice-cold catabatic winds at the ice edge of the glacier lagoon. Catabatic winds are purely density-driven and form when cold air flows down a warmer slope and gains speed as a result. Cold air is heavy and gravity forces it relentlessly to flow down the southern lobe of the ice cap and out over the Jökulsárlón glacial lake. Gale force winds of up to 200 km/h (127 mph or 57 m/s) and temperatures of -8°C (18°F) are not uncommon in such weather conditions. Fifth, the temperature of the lagoon water drops below freezing point, which is below 0°C (32°F) because the lagoon contains brackish water due to its connection to the Atlantic Ocean. The floating icebergs continue to cool the lagoon water and eventually the lagoon freezes over, providing access to the icebergs. Sixth, the storm winds blew black volcanic ash and sand across the Icelandic landscape, accentuating the melting forms of the overturned iceberg into a nature artwork of deep blue ice forms and black patterns of ash. These fascinating structures are most vividly revealed at dusk when the earth’s shadow rises and the sky takes on a violet color.
Wandering through this frozen landscape lies far outside the comfort zone. Spellbound in awe by these fascinating vistas, it is a challenge to withstand the drifting sand, the blowing ashes and the immense cold. In such storm winds at around -8°C (18°F), the perceived temperature drops down to -35°C (-31°F).