zombie apocalypse, Wellington, survivors, fortified town, snowy landscape, barren trees, overcast sky, worn-out clothing, ragged scarves, heavy boots, armed with rifles, cautious stance, lookout towers, makeshift barricades, icy breath, survival tension, desolate atmosphere, cold blue light, distant moans, 3/4 composition, textured snow, rusted metal surfaces, foggy background, high contrast, dramatic shadows.