The surge, which included the liberal dropping of deadly barrel bombs, left analysts and Aleppines wondering if it heralded the start of a new offensive.

“It’s been a while since the regime pounded Aleppo this bad. In the past, the regime has sometimes employed similar aerial campaigns to soften areas it seeks to push into,” says Noah Bonsey, senior Syria researcher for the International Crisis Group. “When you look at a map of where in Aleppo they’re targeting the barrel bombs and the shelling, that’s a possibility.”

The timing is key; a second round of peace talks, to be attended by representatives of both the government and the opposition in exile, are set to begin next month in Montreux, Switzerland. Assad wants to make as many military gains as possible before his team arrives in the Swiss city, to convince the international government that his government is stable.

“They’re trying to strengthen their position ahead of Geneva, and Aleppo’s important for that,” says Andrew Tabler, a senior fellow at the Washington Institute for Near East Policy. “Aleppo is the one city in the west where they don’t control the majority of the city. It’s the largest city in Syria and it’s majority Sunni, which is a special combination. They’re going at their own pace, but they want to demonstrate prowess ahead of Geneva. They’ve sent in some additional ground forces, but it’s mostly through barrel bomb terror campaigns – anything to break the opposition. They’re trying to starve out the opposition, and this week they have the benefit of the worst snowstorm in long time.”

Fighting between the Free Syrian Army and government forces in Aleppo, where the city is split between rebel and opposition control, has been at what many Syria watchers consider a stalemate for months. ISIS and extremist groups have taken advantage and begun their own push into the city, with ISIS fighters stepping in to help the opposition claim Minnagh Air Base this summer after 10 months of fighting. Residential areas here are among the hardest hit by regime air strikes, and historic sites like its ancient souk have been destroyed by cross-fighting.

The city’s largest rebel brigade, Liwa al-Tawhid, recently joined the new Islamic Front, a fighting alliance between seven of Syria’s largest opposition fighting groups. It’s not yet clear whether the Front will provide fighters to ward off the government’s latest push, or whether those reinforcements will be enough to withstand an aerial escalation that will likely continue in the coming weeks.

“Assad’s challenge is that while he has the firepower and enough troops, with help from Hezbollah and Iran, to go on the offensive, can he hold the opposition areas of Aleppo peacefully? I don’t think he can.” Escalating the offensive in Aleppo “is a gamble for the government.”

There is speculation that Assad might also have been influenced by the massacre of civilians including Alawites in Adra, south of Damascus, after an opposition victory there.

“I think also there’s an element of collective punishment when you’re dropping barrel bombs on residential neighborhoods the way the regime has been over the last few days,” Bonsey says.

“Voices within the opposition have suggested that the regime may be hitting especially hard in Aleppo because of rebel gains far to the south, outside of Damascus. The two [battles] would appear to be unrelated, but in pro-regime media and social media there’s been intense focus on Adra, because after the rebels took it there were reports of executions along sectarian lines carried out against civilians. In that context, it is possible that the brutal campaign in Aleppo is partly intended as a show of strength.”