Is the Fall of Avdeevka Significant?
Ukrainian forces have withdrawn suddenly from the Donbas fortress-city of Avdeevka. This is a short distance from Donetsk city and was on the border since the Ukraine Civil War begun after the Maidan Coup in 2014. For almost a decade, Western forces had fortified the city. When Russia did its invasion in 2022, it did not even attempt to advance towards Avdeevka, because there were so many thousands of Ukrainian troops in the area, as Ukraine had been preparing its conquest on the separatist regions.
While there had been irregular battles in the area of the last 2 years, the Russian advance has been around the edges over the last few months. There was some progress in the northwest and the southwest, but nothing major. The Russians have also dropped a lot of large bombs, destroying the fortifications.
Even so, based upon prior battles in fortress-cities, the Ukrainian army should have been able to hold out for months.
Why did the Ukrainians suddenly retreat?
Russia has been fighting a long war of attrition. Russia has superior reserves of troops and ammo and supplies, so could afford 1:1 losses. However, because Russia has local air superiority and a massive advantage in artillery, Ukraine was losing 5 or more for every Russian casualty.
Drafted Ukrainians were often old enough to have lived in the Soviet Union and had little training. They were just thrown into the front.
There is a very real possibility that Ukraine is running out of replacement troops, even untrained ones.
Russians used a lot of glide bombs on Avdeevka. A 500 kiloton bomb does a lot more damage than artillery shells and rockets. While the US has been developing glide bombs for some time, Russia has developed some cheap conversion kits that allow its deep stockpile of bombs to become potent glide bombs. Given that a 500k bomb is .5 megatons, this isn't much different than using battlefield nukes.
Now, perhaps Ukraine’s NATO masters told Ukraine to retreat and shore up defense lines. This is likely only after defeat already was clear.
There was also the sudden retreat of the Azov troops. They had lost 600 in one of their first days in Avdeevka and soon retreated to safety.
Let's not forget the recent leadership shakeup in Ukraine. The retreat could be a result of purely internal factors.
This defeat will matter if Russia follows up with advances up and down the front. That would mean that Ukraine is severely downgraded and is moving to protect a rump Ukraine.
If Russia continues its cautious war of attrition, and is unwilling to push the front-lines further back, then this battle will be forgotten quickly.