A flickering flame of paper, rags and random twigs is the only heat Gulnaz has to keep her 18-month-old son warm, barely visible beneath his icy blanket as she begs on a bitterly cold highway on the road to Kabul.

The 70-kilometer (45-mile) stretch of highway is flanked by snow-swept hills. Occasionally a driver slows his car and shoves an Afghani note into the 28-year-old woman’s bare, dirt-caked hand. She sits for hours on the highway medium, positioned just beyond a bump in the road that slows traffic.

Her 16-year-old sister, Khalida, sits nearby. Both are hidden behind encompassing blue burqas. By the end of the day, Gulnaz, who gave just the one name, says they might make 300 Afghanis ($2.85). But most days it is less.

The Taliban’s sweep to power in Afghanistan in August drove billions of dollars in international assistance out of the country and sent an already dirt-poor nation, ravaged by war, drought and floods, spiraling toward a humanitarian catastrophe.

But in recent weeks it is the bitter winter cold that is devastating the most vulnerable and has international aid organizations scrambling to save millions from starving or freezing because they have neither food nor fuel. For the poorest the only heat or means of cooking is with the coal or wood they can scrounge from the snowy streets or that they receive from aid groups.