diff --git a/scripts/__init_script__.php b/scripts/__init_script__.php
--- a/scripts/__init_script__.php
+++ b/scripts/__init_script__.php
@@ -90,6 +90,9 @@
 
   $handler = new PhutilBacktraceSignalHandler();
   $router->installHandler('phutil.backtrace', $handler);
+
+  $handler = new PhutilConsoleMetricsSignalHandler();
+  $router->installHandler('phutil.winch', $handler);
 }
 
 __phutil_init_script__();
diff --git a/scripts/test/progress_bar.php b/scripts/test/progress_bar.php
--- a/scripts/test/progress_bar.php
+++ b/scripts/test/progress_bar.php
@@ -43,6 +43,19 @@
   echo pht('Caught exception!')."\n";
 }
 
+echo "\n".pht(
+  "RESIZING BARS\n".
+  "If you resize the window while a progress bars draws, it should more or ".
+  "less detect the change.");
+
+$n = 1024;
+$bar = id(new PhutilConsoleProgressBar())
+  ->setTotal($n);
+for ($ii = 0; $ii < $n; $ii++) {
+  $bar->update(1);
+  usleep(10000);
+}
+$bar->done();
 
 function run_interrupt_bar() {
   $bar = id(new PhutilConsoleProgressBar())
diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -177,6 +177,8 @@
     'PhutilConsoleList' => 'console/view/PhutilConsoleList.php',
     'PhutilConsoleLogLine' => 'console/view/PhutilConsoleLogLine.php',
     'PhutilConsoleMessage' => 'console/PhutilConsoleMessage.php',
+    'PhutilConsoleMetrics' => 'console/PhutilConsoleMetrics.php',
+    'PhutilConsoleMetricsSignalHandler' => 'future/exec/PhutilConsoleMetricsSignalHandler.php',
     'PhutilConsoleProgressBar' => 'console/PhutilConsoleProgressBar.php',
     'PhutilConsoleServer' => 'console/PhutilConsoleServer.php',
     'PhutilConsoleServerChannel' => 'console/PhutilConsoleServerChannel.php',
@@ -799,6 +801,8 @@
     'PhutilConsoleList' => 'PhutilConsoleView',
     'PhutilConsoleLogLine' => 'PhutilConsoleView',
     'PhutilConsoleMessage' => 'Phobject',
+    'PhutilConsoleMetrics' => 'Phobject',
+    'PhutilConsoleMetricsSignalHandler' => 'PhutilSignalHandler',
     'PhutilConsoleProgressBar' => 'Phobject',
     'PhutilConsoleServer' => 'Phobject',
     'PhutilConsoleServerChannel' => 'PhutilChannelChannel',
diff --git a/src/console/PhutilConsoleMetrics.php b/src/console/PhutilConsoleMetrics.php
new file mode 100644
--- /dev/null
+++ b/src/console/PhutilConsoleMetrics.php
@@ -0,0 +1,65 @@
+<?php
+
+final class PhutilConsoleMetrics extends Phobject {
+
+  const DEFAULT_CONSOLE = 'default';
+
+  private static $consoles = array();
+
+  private $width = false;
+
+  public static function getNamedConsole($key) {
+    if (!isset(self::$consoles[$key])) {
+      self::$consoles[$key] = new self();
+    }
+
+    return self::$consoles[$key];
+  }
+
+  public static function getDefaultConsole() {
+    return self::getNamedConsole(self::DEFAULT_CONSOLE);
+  }
+
+  public function didGetWINCHSignal() {
+    // When we receive a "WINCH" ("WINdow CHange") signal, clear the cached
+    // information we have about the terminal.
+    $this->width = false;
+
+    return $this;
+  }
+
+  public function getTerminalWidth() {
+    if ($this->width === false) {
+      $this->width = $this->computeTerminalWidth();
+    }
+
+    return $this->width;
+  }
+
+  private function computeTerminalWidth() {
+    if (phutil_is_windows()) {
+      // TODO: Figure out how to do this on Windows.
+      return null;
+    }
+
+    $tmp = new TempFile();
+
+    // NOTE: We can't just execute this because it won't be connected to a TTY
+    // if we do.
+    $err = id(new PhutilExecPassthru('tput cols > %s', $tmp))
+      ->resolve();
+    $stdout = Filesystem::readFile($tmp);
+    unset($tmp);
+
+    if ($err) {
+      return null;
+    }
+
+    $width = (int)trim($stdout);
+    if ($width > 0) {
+      return $width;
+    }
+
+    return null;
+  }
+}
diff --git a/src/console/format.php b/src/console/format.php
--- a/src/console/format.php
+++ b/src/console/format.php
@@ -204,35 +204,6 @@
  * @return int|null Terminal width in characters, or null on failure.
  */
 function phutil_console_get_terminal_width() {
-  static $width;
-
-  if ($width === null) {
-    if (phutil_is_windows()) {
-      // TODO: Figure out how to get this working in Windows.
-      return null;
-    }
-
-    $tmp = new TempFile();
-
-    // NOTE: We can't just execute this because it won't be connected to a TTY
-    // if we do.
-    $err = phutil_passthru('tput cols > %s', $tmp);
-
-    if ($err) {
-      return null;
-    }
-
-    try {
-      $cols = Filesystem::readFile($tmp);
-    } catch (FilesystemException $ex) {
-      return null;
-    }
-
-    $width = (int)$cols;
-    if (!$width) {
-      $width = null;
-    }
-  }
-
-  return $width;
+  return PhutilConsoleMetrics::getDefaultConsole()
+    ->getTerminalWidth();
 }
diff --git a/src/future/exec/PhutilConsoleMetricsSignalHandler.php b/src/future/exec/PhutilConsoleMetricsSignalHandler.php
new file mode 100644
--- /dev/null
+++ b/src/future/exec/PhutilConsoleMetricsSignalHandler.php
@@ -0,0 +1,14 @@
+<?php
+
+final class PhutilConsoleMetricsSignalHandler extends PhutilSignalHandler {
+
+  public function canHandleSignal(PhutilSignalRouter $router, $signo) {
+    return ($signo === SIGWINCH);
+  }
+
+  public function handleSignal(PhutilSignalRouter $router, $signo) {
+    PhutilConsoleMetrics::getDefaultConsole()
+      ->didGetWINCHSignal();
+  }
+
+}
diff --git a/src/future/exec/PhutilSignalRouter.php b/src/future/exec/PhutilSignalRouter.php
--- a/src/future/exec/PhutilSignalRouter.php
+++ b/src/future/exec/PhutilSignalRouter.php
@@ -18,6 +18,7 @@
       if (function_exists('pcntl_signal')) {
         pcntl_signal(SIGHUP, array($router, 'routeSignal'));
         pcntl_signal(SIGTERM, array($router, 'routeSignal'));
+        pcntl_signal(SIGWINCH, array($router, 'routeSignal'));
       }
 
       self::$router = $router;