KATMANDU, Nepal — Nepalese officials closed a section of a popular Himalayan trekking route Sunday after rescuers, overwhelmed with last week’s snowstorms that killed at least 38 people, had to save new hikers who set out after the blizzards on the same deadly trails. The dead from the blizzards and avalanches that hit the upper section of the Annapurna trekking circuit in northern Nepal included foreign trekkers, local guides and villagers.