In 822, a great winter came to Ireland- a winter so strong and cold it caused a famine according to Francis Ludlow, a Yale Historical Climatologist. Ludlow told Irish State TV RTE that the weather was a major factor in the famine which followed the intense winter. He used information from the medieval history manuscript called the Annals of Uster, which reported an unusual amount of snow and ice in 818. By 825, it recorded a mass famine and high mortality rates.
Waist high snowfall in 822 led to Irish famine and death – IrishCentral.com.