The Spring fire developed in northern Costilla County in south-central Colorado during the late afternoon of 6/27/2018. The fire quickly grew to over 1,000 acres by evening. GOES-16 captured the initial development of the wildfire hot spot (Figure 1) and associated smoke plume (Figure 2).
By the afternoon of the 28th, the fire had grown to over 4,000 acres with no containment, and destroyed an estimated 30 structures. Given the dry and breezy conditions, NWS Pueblo had issued a Red Flag Warning for much of the region. Although the lower levels were very dry, moisture aloft led to the development of clouds in the area, and pyrocumulus at times over the fire. GOES-16 1-min imagery was available over the region on the 28th, and visible imagery captured the convective bursts (Figure 3).

Figure 3: 28 June 2018 GOES-16 1-min VIS over south-central Colorado. Centered over Spring Fire, located in far northeast Costilla County. Full res
Despite the cloud cover, the hot spot associated with the fire was still apparent much of the day in the 3.9 um channel (Figure 4)
The hot spot was also detected by the Suomi-NPP Day Night Band (Fig 5).

Figure 5: 29 June 2018 overnight Suomi-NPP Day Night Band over eastern Colorado. Image credit: William Straka (UW/SSEC/CIMSS). Full res
By the evening of Friday the 29th, the fire had grown to nearly 34,000 acres. While cloud cover remained over the region, the hot spot was still apparent as it expanded. The hot spot remained apparent through the evening (Fig 6).

Figure 6: 30 June 2018 GOES-16 5-min 3.9 um shortwave IR imagery centered over Spring Fire. Full res
The fire grew to over 41,000 acres on June 30th. GOES-16 3.9 um channel imagery indicated two distinct hot spot areas become obvious during the day (Fig 7). The fire remains 0% contained.

Figure 7: 30 June 2018 GOES-16 5-min 3.9 um SWIR over Spring Fire. Full res
Bill Line, NWS