Dzud

Primary reference(s)

Natsagdorj, L. and J. Dulamsuren, 2001. Some aspects of assessment of the dzud phenomena. Pap Meteorol Hydrol 23:3-18 [in Mongolian].

Nandintsetseg, B., M. Shinoda and B. Erdenetsetseg, 2017. Contributions of multiple climate hazards and overgrazing to the 2009/2010 winter disaster in Mongolia. Natural Hazards, 92:109- 126

Nandintsetseg, B., M. Shinoda, Ch. Du and E. Munkhjargal, 2018a. Cold-season disasters on the Eurasian steppes: Climate-driven or man-made. Scientific Reports, 8:14769.

Nandintsetseg, B., M. Shinoda and B. Erdenetsetseg, 2018b. Developing an early warning system of
Dzud (cold-season disaster) in Mongoliadoi: 10.13140/RG.2.2.33661.72161.

Additional scientific description

There is a conventional classification of dzud types based on direct factors contributing to conditions that prevent animals from grazing for consecutive days, finally resulting in their starvation. These include (Fernandez-Gimenez et al., 2011):

• White dzud defined as conditions during which grasses that grow during the summer and decay during the subsequent cold season are covered by deep snow, preventing grazing. The snow depth during these conditions substantially exceeds plant height. This is the most common and disastrous dzud type.
• Iron (or glass) dzud happens when grasses are covered with impenetrable ice that is produced through melted and refrozen snow (most likely occurring during spring and autumn).
• Black dzud refers to freezing temperatures and lack of snow in winter (essential for livestock and human water) and limited forage/pasture due to preceding summer drought.
• Storm and cold dzuds both tend to result from strong winds and blizzard, and cold surge conditions. These weather patterns reduce the intake of pasture by livestock, which is determined by the availability of phytomass (i.e., not covered by snow and ice) and grazing time.
• Hoof dzud is primarily associated with lack of pasture, often caused by overgrazing. This may occur when an excessive number of animals are concentrated in relatively good but limited pasturelands.

A combined (or multiple) dzud occurs when two or more of the above types of dzud occur together.

Note: human-induced vulnerability, including inadequate pasture management, lack of herder experience, poverty, and insufficient winter preparedness can increase the risks of dzud impacts.

Metrics and numeric limits

Not available.

Examples of drivers, outcomes and risk management

A dzud is a compound hazard occurring in a cold dry climate, and encompassing drought, heavy snowfall, extreme cold, and windstorms. It can last all year round and can cause mass livestock mortality and dramatic socioeconomic impacts – including unemployment, poverty, and mass migration from rural to urban areas, giving rise to heavy pressure on infrastructure and social and ecosystem services (Murray et al., 2012). Dzuds occurred in Mongolia in 1944–1945, 1954–1955, 1956–1957, 1967–1968, 1976–1977, 1986–1987, 1993–1994, and 1996–1997. The dzud of 1944–1945 was a record for the 20th century with mortality of one-third of Mongolia’s total livestock, with the 2009–2010 dzud causing similarly high animal mortality (Murray et al., 2012).