growing concern

• warning signsIndicators of impending danger
• red flagsIndicators something's wrong
• creeping dreadSlowly intensifying fearful anticipation
• nagging doubtPersistent, low-grade uncertainty
• ripple effectCascading secondary results

gathering storm · public outcry · wake-up call · tipping point · troublesome · worrisome · unsettling · attention · awareness · scrutiny · epidemic · crisis · erosion · deterioration