"HIMWARC will extend our fundamental knowledge and concomitantlyrestrain present levels of uncertainty with respect to future changes of highimpact weather in the Arctic.The weather in the Arctic features several severe types of extremes suchas polar lows and strong low-level winds in the vicinity of topography. Theseextremes rigorously influence the socio-economic structure of the affectedregions and communities by extensive material damages and loss of lives.Our current understanding of the formation and intensification of theseweather phenomena is still at an infant level, which limits our forecastingcapabilities and hence restrains our abilities of mitigation measures.Furthermore, a detailed and comprehensive assessment of changes withrespect to high impact weather in the Arctic in a future climate will also belimited to our understanding of the underlying processes giving rise to thesephenomena.HIMWARC´s approach is twofold. Firstly, extending our fundamentalunderstanding of high impact weather in the Arctic. Secondly, incorporatingnovel findings into improved diagnostics to assess future changes in spatialdistribution, frequency and intensity of Arctic severe events. The pursuitof these goals is aided by the affiliation of HIMWARC with THORPEX, aWWRP initiative by the WMO, and its recently established Polar Project.HIMWARC builds on previous efforts by IPY-THORPEX via use of its fieldcampaign data and sustaining established scientific network betweenresearch institutions and forecasting agencies.Outcomes of HIMWARC will be: (i) revised and unified theory on polarlow genesis by incorporating a novel concept to the formation process; (ii)better understanding of the interactions between atmospheric flow withsteep topography in the light of extreme wind events and cyclogenesis;(iii) assessment of future changes of high impact weather in the Arctic; (iv)determine the influence of high impact weather on the ocean circulation."