def reproject_prec(pre_df, new_crs='epsg:26910'):
    """Reproject to a CRS with units as meters and add area column (needed for pop density variable)
    new_crs(int): desired reprojected crs
    """
    pre_df = pre_df.to_crs({'init': new_crs})  
    pre_df['area_m']=pre_df.geometry.area
    return(pre_df)