BERLIN—More than 20 people have died and dozens of people are missing in Germany and neighboring Belgium after heavy flooding turned streams and streets into raging torrents, sweeping away cars and causing buildings to collapse. Storms across parts of western Europe in recent days caused rivers and reservoirs to burst their banks, resulting in flash floods as rain-soaked soil failed to absorb any more water. Authorities in the western German region of Euskirchen said Thursday that eight deaths had been reported there in connection with the floods. Rescue operations were hampered by the fact that phone and internet connections were down in parts of the county, which is southwest of Cologne. Police in the western city of Koblenz said four people had died in Ahrweiler county. Up to 70 people were reported missing after several houses collapsed overnight in the village of Schuld in the Eifel, a volcanic region of …