With increased urbanisation, fires in the wildland urban interface (WUI) have become a severe problem worldwide. The unique features of WUI may influence fire-atmosphere interactions. This study utilises the parallelized large eddy simulation model (PALM) system for fire-atmosphere simulations of Bottle Lake Forest, Christchurch, New Zealand. Over 3000 residential buildings are situated around the 7 km2 forest, with many homes only 50 m away from the forest edge. We conducted high-fidelity fire-atmosphere simulations with the finest grid spacing of 4 m. In comparison to WUI simulations, flat terrain simulations were carried out as a reference for idealised scenarios. Fire-weather conditions for the 2022/2023 New Zealand fire season were selected based on the Fire Weather Index (FWI). Data from previous fire field campaigns were obtained to represent the fire heat forcing. Our results show that the WUI simulation coincides with fire heat transport going further downwind than its flat terrain counterpart. Kelvin-Helmholtz waves were present in both the WUI and flat terrain simulations, generating downdrafts from higher levels to the surface. However, downwind heat transport coincides with a pulsing behavior only in the WUI. In addition to these characteristics, analysis of the ambient atmosphere shows that the WUI plays the main role in modifying fire-atmosphere interactions. This study is the first to simulate fire-atmosphere interactions in WUI with such a high fidelity. Our results provide insights into the impact of WUI on fire-atmosphere dynamics. More work is needed to further understand how each component of WUI can alter fire-atmosphere interactions.