"Thank God, this year we have grass," the herder said on a livestock reserve in northern Senegal as plump cows munched the pasture behind him. Abundant rains soaked West Africa's Sahel region in recent months, causing catastrophic floods in some areas that raised concerns about the rising costs of extreme weather. But this year's downpours also created the thickest vegetation in years, satellite data show - a vital respite for Senegal's farmers and its 3 million-strong herding community after six years of drought. Since the early 1980s, the frequency of storms has tripled in the Sahel, according to a study here in the journal Nature, which said the trend was consistent with what scientists expect from human-driven climate change. Herders are not used to unexpected benefits in the Sahel, whose semi-arid prairies stretch eastwards from Senegal across some of the world's poorest countries. The successive droughts in Senegal and neighbouring Mauritania and a particularly long dry season before the latest rains have helped permanently weaken pastoral livelihoods across the whole region, according to aid agency Action Against Hunger. Meanwhile rising temperatures mean some areas could become as hot as the Sahara Desert within 80 years, according to a study in the online journal Climatic Change published in October. This year, though, things are looking up. RECORD VEGETATION Sow's long-horned white cows do not have to walk far to fill their bellies as they roam the sun-baked fields studded with acacia and baobab trees. Cattle and sheep on the reserve are at their fattest in recent memory. The heavy rain has encouraged zornia, a nutritious plant with slender leaves that herders feared was becoming scarce, said local vet Mawdo Ngom. "This time last year the grass was already dry," Sow said in late November. The rains have also boosted other sectors. Grains output is expected to jump over 30 percent this year, prompting Senegal to reverse its economic outlook for 2020 from contraction to growth. Vegetation levels have hit record highs this year in more central parts of the Sahel, including Niger and Chad, the satellite data from Action Against Hunger show. This should have proved a blessing for the two-thirds of the region's population dependent on farming or herding. But conflict across Mali, Burkina Faso and Niger has cut off access to farms and displaced communities. Partly as result of this, the region is facing its worst food crisis in a decade with potentially over 23 million people needing aid to survive the upcoming dry season, according to the Cadre Harmonise, a regional food security framework under the auspices of the United Nations. DRYING HEAT Dramatic climate swings year to year are normal for the Sahel, making it hard to assess the impact of climate change on current conditions or predict what Senegal should prepare for in the long term, climate scientist Sylwia Trzaska of Columbia University's Earth Institute said. "We are very uncertain about which way the rainfall is going to evolve, but temperatures are rising, especially during the dry season, that's a given," she said. Senegal has escaped the violence devastating its neighbours, but some herders doubt the sustainability of their way of life given their struggle to get through recent dry seasons. Sitting in his family's traditional home of woven branches, herder Dioubeyrou Ka, 67, said drought has made it hard to find the long-stalked plant needed to thatch his roof. "Often we went in our carts from morning till night, searching for water so our children could have a drink," he said, tossing back thimble-sized glasses of tea. If dry seasons keep getting hotter as projected under climate models, water resources will dry out quicker during these periods, putting additional pressure on herders and their livestock, Trzaska said. On the reserve, where some herders have settled, Ngom says it's quiet. Earlier in the year nomadic herders desperate for pasture came in droves, piling children, possessions and baby goats onto carts pulled by three donkeys abreast. He does not expect such numbers this season. "Herders - if nature smiles on them, they forget all their problems," said the vet, strolling past cows he deemed to be reassuringly stout.