There are no official natural ice surfaces on the Danube waterways that have been cleared for skating, so it is safe to state that this woman did so at her own risk. In fact, there are no areas along the tributaries of the Danube that are checked for safety at all. According to an ORF report, even the ice on the city's plastic-based, artificial skating rinks have unreliable consistency and thereby risky safety conditions.
In the case of the ice-covered Danube, the ice remains quite thin because the still water that lies underneath is unaffected by air temperatures and hovers at around seven degrees Celsius, even in extreme cold. The Alte Donau is four meters deep, and the Neue Donau measures down to seven meters below.
Gerald Loew, the manager of MA 45, Vienna's administrative department that supervises bodies of water, stated: “Even we, as experts, cannot confirm the strength of the ice, given the myriad of factors involved. The probability of falling through is nevertheless high.”